Nonwoven substrates having fibrils

ABSTRACT

The present invention relates to a nonwoven substrate comprising a layer of fibers, wherein a plurality of the fibers each comprise a plurality of fibrils extending outwardly from a surface of the fibers, and wherein the plurality of fibrils comprise a lipid ester.

The present disclosure generally relates to nonwoven substrates andmethods for forming the same, and the use of said nonwoven substrates inarticles of commerce, such as absorbent articles and wipes, and packagesand packaging materials for the articles of commerce.

Nonwoven substrates may be useful in a wide variety of applications.Various nonwoven substrates may comprise spunbond-meltblown-spunbond(“SMS”) substrates comprising outer layers of spunbond thermoplastics(e.g., polyolefins) and interior layers of meltblown thermoplastics.Some nonwoven substrates, either in addition to or in place of themeltblown thermoplastics, may comprise fine fibers (i.e., fibers havinga diameter of less than one micrometer (“N-fibers”) to create “SMNS”substrates or “SNS” substrates, for example. Such nonwoven substratesmay comprise spunbond layers which are durable and internal meltblownlayers and/or fine fiber layers which are porous but which may inhibitfast strikethrough of fluids, such as bodily fluids, for example, or thepenetration of bacteria through the nonwoven substrates.

Absorbent articles such as diapers, training pants, adult incontinenceproducts, and feminine hygiene products utilize nonwoven substrates formany purposes. For many applications, the barrier properties of thenonwoven substrates play an important role in the performance of thenonwoven substrates, such as the performance as a barrier to fluidpenetration, for example. Absorbent articles may comprise multipleelements such as a liquid pervious material or topsheet intended to beplaced next to the wearer's skin, a liquid impervious material orbacksheet intended to be placed proximate to or on the outer surface ofthe absorbent article, various barrier layers or cuffs, and an absorbentcore disposed at least partially intermediate the liquid perviousmaterial and the liquid impervious material.

Frequently, films, such as elastomeric films, are used in themanufacturing of various components of absorbent articles and otherarticles of commerce. For example, films may be used in liquid perviouslayers, liquid impervious layers, barrier cuffs, barrier layers, sidepanels, or in other components of absorbent articles or other articlesof commerce. Films provide a high resistance to fluid flow and thusoffer ideal barrier performance. This applies even to formed, aperturedfilms where the film area around the apertures provides excellentprotection against fluid flow and rewet. Films, however, are quiteexpensive and less comfortable to a wearer compared to nonwovensubstrates. As such, manufacturers of articles of commerce thatincorporate films are usually trying to reduce the amount of the filmsin their products. What is needed are nonwoven substrates that canmatch, or come close to matching, the specific advantageous propertiesof the films, such as low surface tension fluid strikethrough times,while providing comfort to the users and cost advantages tomanufacturers. Also, what is needed are nonwoven substrates that havelower basis weights compared to conventional nonwoven substrates, butthat have the same fluid strikethrough times as the conventionalnonwoven substrates to again save material costs for manufacturers.

Articles of commerce, such as wipes (including cleaning substrates), forexample, use nonwoven substrates for various applications, such ascleaning, scrubbing, and/or applying a compound, for example. Manydrawbacks exist in these nonwoven substrates. As such, these nonwovensubstrates should be improved such that they have more beneficialproperties and allow for better cleaning, scrubbing, dirt retention,and/or application properties.

In some instances, packaging materials for articles of commerce usepolymeric films. Films provide a high resistance to fluid and air flowand thus are ideal packaging materials for articles of commerce. Films,however, are quite expensive and are not as aesthetically pleasingcompared to nonwoven substrates. As such, manufacturers of articles ofcommerce that use films as packaging materials are usually trying toreduce the amount of the films required in their packaging materialsand/or achieve more aesthetically pleasing films. What is needed arenonwoven substrates that can function like films, or substantially likefilms, and that are aesthetically pleasing, but that can be manufacturedmuch cheaper than conventional polymeric films.

The above-mentioned and other features and advantages of the presentdisclosure, and the manner of attaining them, will become more apparentand the disclosure itself will be better understood by reference to thefollowing description of non-limiting embodiments of the disclosuretaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram of a forming machine used to make anonwoven substrate in accordance with a non-limiting embodiment;

FIG. 2 is an example cross-sectional view of a nonwoven substrate in athree layer configuration in accordance with a non-limiting embodiment;

FIG. 3 is a perspective view of the nonwoven substrate of FIG. 2 withvarious portions of nonwoven layers cut away to show the composition ofeach non woven layer in accordance with a non-limiting embodiment;

FIG. 4 is a cross-sectional view of a nonwoven substrate in a four layerconfiguration in accordance with a non-limiting embodiment;

FIG. 5 is a perspective view of the nonwoven substrate of FIG. 4 withvarious portions of nonwoven layers cut away to show the composition ofeach non woven layer in accordance with a non-limiting embodiment;

FIGS. 6-8 are scanning electron microscope (“SEM”) photographs of anonwoven substrate having fibrils in spunbond layers thereof inaccordance with various non-limiting embodiments;

FIGS. 9-11 are additional SEM photographs of a nonwoven substrate havingfibrils in spunbond layers thereof in accordance with variousnon-limiting embodiments;

FIGS. 12-14 are SEM photographs of cross-sectional views of portions ofa non woven substrate having fibrils in spunbond layers thereof inaccordance with various non-limiting embodiments;

FIG. 15 is a SEM photograph of a portion of a bond site having a bondarea, wherein a plurality of fibrils extend from the bond area inaccordance with a non-limiting embodiment;

FIGS. 16-18 are SEM photographs of cross-sectional views of portions ofa bond site having a bond area of a nonwoven substrate, wherein aplurality of fibrils ex tend from the bond area in accordance withvarious non-limiting embodiments;

FIG. 19 is an example graph of the impact of the melt additive glyceroltristearate on specific surface area of nonwoven substrates of thepresent disclosure corn pared to the specific surface area ofconventional nonwoven substrates without any glycerol tristearate inaccordance with a non-limiting embodiment;

FIG. 20 is an example graph of low surface tension fluid strikethroughtime (seconds) to basis weight (gsm) ratio (seconds/gsm) to the amountof glycerol tristearate (gsm) in a nonwoven substrate in accordance witha non-limiting embodiment;

FIG. 21 is an example graph of specific surface area (m²/g) to time(hours) post-nonwoven substrate or nonwoven layer formation for nonwovensubstrates of the present disclosure in accordance with a non-limitingembodiment;

FIG. 22 is an example bar graph of low surface tension fluidstrikethrough times (seconds) on various nonwoven substrates of thepresent disclosure corn pared to a conventional SMS 13 gsm nonwovensubstrate in accordance with a non-limiting embodiment;

FIG. 23 is an example graph of low surface tension fluid strikethroughtimes (seconds) based on the glycerol tristearate percentages by weightof the composition used to form the fibers in accordance with anon-limiting embodiment;

FIG. 24 is an example graph of low surface tension fluid strikethroughtimes (seconds) based on the percentages of glycerol tristearate byweight of the corn position used to form the fibers in accordance with anon-limiting embodiment. The bottom line represents a 19 gsm spunbondnonwoven substrate. The middle line represents a 16 gsm spunbondnonwoven substrate. The top line represents a 13 gsm spunbond nonwovensubstrate.

FIG. 25 is an example graph of low surface tension fluid strikethroughtimes (seconds) based on fiber diameters (μm) in accordance with anon-limiting embodiment;

FIG. 26 is an example graph of low surface tension fluid strikethroughtime (seconds) based on the amount of glycerol tristearate (gsm) withinvarious non woven substrates in accordance with a non-limitingembodiment;

FIG. 27 is a perspective view of a package for articles of commerce,wherein a portion of the package may comprise the nonwoven substrates ofthe present disclosure in accordance with a non-limiting embodiment;

FIG. 28 is an SEM photograph of a cross-sectional view of a nonwovensubstrate of the present disclosure, wherein the lipid esters in thespunbond fibers have been dissolved using a gravimetric weight lossmethod in accordance with a non-limiting embodiment;

FIG. 29 is an SEM photograph of a cross-sectional view of a spunbondfiber of FIG. 28 in accordance with a non-limiting embodiment;

FIG. 30 is an example graph of mass-average fiber diameter (X-axis) tospecific surface area (Y-axis) in accordance with a non-limitingembodiment; and

FIG. 31 is a view of an orifice used in the Low Surface Tension FluidStrikethrough Time Test described herein.

Various non-limiting embodiments of the present disclosure will now bedescribed to provide an overall understanding of the principles of thestructure, function, manufacture, and use of the nonwoven substrates andmethods for forming the same disclosed herein. One or more examples ofthese non-limiting embodiments are illustrated in the accompanyingdrawings. Those of ordinary skill in the art will understand that thenonwoven substrates and methods for forming the same specificallydescribed herein and illustrated in the accompanying drawings arenon-limiting example embodiments and that the scope of the variousnon-limiting embodiments of the present disclosure are defined solely bythe claims. The features illustrated or described in connection with onenon-limiting embodiment may be combined with the features of othernon-limiting embodiments. Such modifications and variations are intendedto be included within the scope of the present disclosure.

In this description, the following terms have the following meanings:

The term “absorbent article” refers to disposable devices such asinfant, child, or adult diapers or incontinence products, trainingpants, sanitary napkins, tampons, and the like which are placed againstor in proximity to the body or a natural orifice of the body of thewearer to absorb and contain the various exudates (e.g., urine, BM,menses) discharged from the body. Certain absorbent articles maycomprise a topsheet or liquid pervious layer, a backsheet or liquidimpervious layer, and an absorbent core positioned at least partiallyintermediate the topsheet and the backsheet. The articles may alsocomprise an acquisition system (which may be comprised of one or severallayers), and typically other components. Example absorbent articles ofthe present disclosure will be further illustrated in the belowdescription and in the figures in the form of a taped diaper and asanitary napkin. Nothing in this description should be consideredlimiting the scope of the claims based on the example absorbent articlesillustrated and described. As such, the present disclosure applies toany suitable form of absorbent articles (e.g., training pants, adultincontinence products, sanitary napkins). For the avoidance of doubt,absorbent articles do not include wipes. Wipes are defined hereinafterand are also within the scope of present disclosure.

The term “ambient conditions” is defined as typical post-nonwovensubstrate and/or absorbent article manufacturing conditions, nonwovensubstrate and/or absorbent article storage conditions, and morespecifically 20 degrees C.+/−7 degrees C. at a relative humidity of50%+/−30%.

The term “article of commerce” includes any products, such as absorbentarticles, wipes (wet or dry), cleaning or dusting substrates, filters,filter media, toothbrushes, or batteries, for example.

The term “basis weight” is defined by the Basis Weight Test set forthbelow. Basis weight is set forth in grams/m² (gsm).

The term “bond area” refers to the area of an individual bond site.

The term “cross direction” refers to a direction that is generallyperpendicular to the machine direction.

The term “diameter” when referring to fibers is defined by the FiberDiameter and Denier Test set forth below. Diameter of fibers is setforth in microns.

The term “elastic strand” or “elastic member” refers to a ribbon orstrand (i.e., great length compared to either width and height ordiameter of its cross-section) as may be part of the inner or outer cuffgathering component of an article.

The term “fiber” refers to any type of artificial fiber, filament, orfibril, whether continuous or discontinuous, produced through a spinningprocess, a meltblowing process, a melt fibrillation or film fibrillationprocess, or an electrospinning production process, or any other suitableprocess.

The term “film” refers to a polymeric material, having a skin-likestructure, and it does not comprise individually distinguishable fibers.Thus, “film” does not include a nonwoven material. For purposes herein,a skin-like material may be perforated, apertured, or micro-porous andstill be deemed a “film.”

The term “fibrils” refers to projections, elongate projections, or bumpsthat extend outwardly from a surface or generally radially outwardlyfrom an outer surface of a fiber. In some instances, the projections,elongate projections, or bumps may extend radially outwardly relative toa longitudinal axis of the fiber. Radially outwardly means in the rangeof 1 to 89 degrees relative to the longitudinal axis. In still otherinstances, the projections, elongate projections, or bumps may extendradially outwardly from a surface of a fiber at least in a longitudinalcentral third of the fiber. The projections, elongate projections, orbumps comprise, consist of, or consist essentially of (e.g., 51% to 100%or 51% to 99%), melt additives, such as lipid esters. The projections,elongate projections, or bumps grow from the fibers post-nonwovensubstrate formation only after a time period (e.g., 6-100 hours) underambient conditions. Fibrils can be viewed using an SEM at, at least1,000 times magnification.

The term “hydrophobic” refers to a material or composition having acontact angle greater than or equal to 90° according to The AmericanChemical Society Publication “Contact Angle, Wettability, and Adhesion,”edited by Robert F. Gould and copyrighted in 1964. In certainembodiments, hydrophobic surfaces may exhibit contact angles greaterthan 120°, greater than 140°, or even greater than 150°. Hydrophobicliquid compositions are generally immiscible with water. The term“hydrophobic melt additive” refers to a hydrophobic composition that hasbeen included as an additive to a hot melt composition (i.e., blendedinto a thermoplastic melt), which is then formed into fibers and/or asubstrate (e.g., by spunbonding, meltblowing, melt fibrillation, orextruding).

The term “hydrophobic surface coating” refers to a composition that hasbeen applied to a surface in order to render the surface hydrophobic ormore hydrophobic. “Hydrophobic surface coating composition” means acomposition that is to be applied to a surface of a substrate, such as anonwoven substrate, in order to provide a hydrophobic surface coating.

The term “joined” or “bonded” or “attached”, as used herein, encompassesconfigurations whereby an element is directly secured to another elementby affixing the element directly to the other element, andconfigurations whereby an element is indirectly secured to anotherelement by affixing the element to intermediate member(s) which in turnare affixed to the other element.

The term “low surface tension fluid” refers to a fluid having a surfacetension of 32 mN/m+/−1.0 mN/m.

The term “low surface tension fluid strikethrough time” is defined bythe Low Surface Tension Fluid Strikethrough Time Test set forth below.Low Surface Tension Fluid Strikethrough Time is set forth in seconds.

The term “machine direction” (MD) refers to the direction of materialflow through a process.

The term “calender bond” or “thermal bond” refers to a bond formedbetween fibers of a nonwoven by pressure and temperature such that thepolymeric fibers within the bond melt or fuse together to form acompressed, flat area which may be a continuous film-like material. Theterm “calender bond” does not comprise a bond formed using an adhesivenor through the use of pressure only as defined by mechanical bondbelow. The term “thermal bonding” or “calender bonding” refers to theprocess used to create the thermal bond.

The term “mechanical bond” refers to a bond formed between two materialsby pressure, ultrasonic attachment, and/or other mechanical bondingprocess without the intentional application of heat. The term mechanicalbond does not comprise a bond formed using an adhesive.

The term “layer” refers to one sheet or ply of a nonwoven or othermaterial.

The term “substrate” refers to a sheet-like structure of one or morelayers such as a nonwoven substrate.

The term “titer” refers to the longitudinal density as measured in termsof mass per unit length of a fiber.

The term “denier” refers to a unit of fineness of a fiber that is equalto the weight (in grams) per 9000 m of fiber.

The term “mass-average diameter” refers to a mass-weighted arithmeticmean diameter of fibers calculated from the fiber diameter, which ismeasured by the Fiber Diameter and Denier Test set forth below.Mass-average diameter of fibers is calculated by the Fiber DiameterCalculations set forth below. The mass-average diameter of fibers is setforth in microns.

The term “number-average diameter,” alternatively “average diameter”,refers to an arithmetic mean diameter of fibers calculated from thefiber diameter, which is measured by the Fiber Diameter and Denier Testset forth below. Number-average diameter of fibers is calculated by theFiber Diameter Calculations set forth below. The number-average diameterof fibers is set forth in microns.

Nonwoven substrates that have properties that are the same as or comeclose to matching some film properties are desired. One film propertythat would be advantageous in a nonwoven material is the film's abilityto be fluid impervious or substantially fluid impervious. Films aretypically less breathable, less comfortable, and generally noisier undermovement than nonwoven materials, unless rendered more nonwoven-likewith expensive manufacturing methods. As such, nonwoven materials thathave film-like, or close to film-like, fluid permeability properties aredesired because of the huge cost savings and greater comfort to the userassociated with the same. In an embodiment, the present disclosureprovides nonwoven substrates having increased fluid barrier properties.In another embodiment, the present disclosure provides nonwovensubstrates having one or more layers of fibers, wherein the nonwovensubstrates have certain specific surface areas that are higher thanspecific surface areas of conventional nonwoven substrates. In anembodiment, a nonwoven substrate of the present disclosure may compriseone or more layers of fibers, wherein a plurality of fibrils may extendoutwardly, or radially outwardly, from a surface of at least some of thefibers in the one or more layers of fibers. The fibrils can lead todecreased fluid (i.e., liquid or gas) permeability, especially liquid,in the layer of fibers and the nonwoven substrate as a whole. A nonwovensubstrate may have all layers having fibers comprising fibrils or lessthan all layers having fibers with fibrils. Stated another way, somelayers may have fibers that are free of fibrils while other layers mayhave fibers with fibrils. Some layers may have fibers with fibrils andfibers without fibrils. The specific surface areas of the nonwovensubstrates and the fibers with fibrils will be discussed in furtherdetail below after a more general description of an example absorbentarticle for use with the nonwoven substrates of the present disclosure.Wipes, packages, and packaging materials that use the nonwovensubstrates discussed herein are also within the scope of the presentdisclosure. These will also be discussed in further detail below.

Nonwoven substrates may comprise sheets of individual nonwoven layers offibers, filaments, or a combination of fibers and filaments, bondedtogether using mechanical, thermal, or chemical bonding processes.Nonwoven substrates may be formed as relatively flat, porous sheets madedirectly from individual fibers, including staple fibers, directly frommolten plastic, from plastic films, and/or some combination of theaforementioned. Some nonwoven substrates may be strengthened orreinforced by a backing sheet, for example. Nonwoven substrates may beengineered fabrics that may be a limited life, single-use fabrics, or avery durable, reusuable fabrics. In various embodiments, nonwovensubstrates provide specific functions, such as absorbency, liquidrepellency, resilience, stretch, opacity softness, and/or strength.These properties are often combined to create nonwoven substrates suitedfor specific applications, while achieving a good balance betweenproduct useful life and cost. A thorough list of nonwoven manufacturingprocesses is described in “The Handbook of Nonwovens” edited by S. J.Russell and published by Woodhead Publishing Limited and CRC Press LLC(ISBN: 978-0-8493-2596-0), for example.

Direct Polymer to Wet-Laid Nonwoven Materials

Continuous and discontinuous fiber spinning technologies of moltenmaterials and typically of thermoplastics are commonly referred to asmeltspinning or spunmelt technologies. Spunmelt technologies maycomprise both the meltblowing process and the spunbonding processes. Aspunbonding process comprises supplying a molten polymer, which is thenextruded via a die under pressure through a large number of orifices ina plate known as a spinneret. The resulting continuous fibers arequenched and drawn by any of a number of methods, such as slot drawsystems, attenuator guns, or drawing rolls (Godet), for example. In thespunlaying or spunbonding process, the continuous fibers are collectedas a loose web upon a moving foraminous surface, such as a wire meshconveyor belt, for example. When more than one spinneret is used in linefor forming a multi-layered nonwoven substrate, the subsequent nonwovenlayers are collected upon the uppermost surface of the previously formednonwoven layer. Spunlaid or spunbond nonwoven substrates may bemulti-component (e.g., like a core and a sheath, or a segmented pie orislands-in-the-sea), multi-constituent (i.e., blends of multiplechemicals in one component), as well as have a variety of cross-sectionsbesides round or circular, such as tri-lobal, oval or hollow. Examplesof manufacturing such a wide range of spunlaid layers or fabrics aredescribed in U.S. Pat. No. 3,502,763 to Hartmann et al., U.S. Pat. No.3,692,618 to Dorschner et al., U.S. Pat. No. 3,338,992 to Kinney, U.S.Pat. No. 4,820,142 to Balk, U.S. Pat. No. 5,460,500 to Geus et al., U.S.Pat. No. 6,932,590 to Geus et al., U.S. Pat. No. 5,382,400 to Pike etal., U.S. Pat. No. 7,320,581 to Allen et al., and U.S. Pat. No.7,476,350 to Allen.

The meltblowing process is related to the spunlaying or spunbondingprocess by forming a layer of a nonwoven substrate, wherein a moltenpolymer is extruded through orifices in a spinneret or a die, typicallywith a single row of small orifices in the die. A high flow rate of hot,high velocity gas impinges upon and attenuates the fibers as they exitthe die, and quickly draws them to micro-fibers of diameters on theorder of one to ten micrometers and of indeterminate length. Thisdiffers from the spunbonding process where the continuity of the fibersis generally preserved. The fibers are then blown and deposited by thehigh velocity air onto a collector, conveyor, or other web.

Often meltblown nonwoven layers are added to spunlaid nonwoven layers toform spunbond-meltblown (“SM”) nonwoven substrates orspunbond-meltblown-spunbond (“SMS”) nonwoven substrates, which combinethe attributes of S and M nonwoven structures, e.g., strong nonwovensubstrates with some barrier properties. Descriptions for making suchmeltblown fibers, layers, and nonwoven substrates can be found forexample in: “Superfine Thermoplastic Fibers”, by Van A. Wente, in Ind.Eng. Chem. Res. 48 (8) 1956, pp. 1342-46, or in U.S. Pat. No. 3,849,241to Buntin et al. and U.S. Pat. No. 5,098,636 to Balk.

Other methods to produce even finer fibers, including fibers withaverage diameters less than one micron or 1000 nanometers (an“N-fiber”), may comprise melt fibrillation, advanced meltblowingtechnology, or electrospinning. Advanced melt-blowing technology isdescribed, for example, in U.S. Pat. No. 4,818,464 to Lau, U.S. Pat. No.5,114,631 to Nyssen et al., U.S. Pat. No. 5,620,785 to Watt et al., andU.S. Pat. No. 7,501,085 to Bodaghi et al.

Melt film fibrillation technology, as example of melt fibrillation, is ageneral class of making fibers defined in that one or more polymers aremolten and are extruded into many possible configurations (e.g., hollowtubes of films, sheets of films, co-extrusion, homogeneous orbicomponent films or filaments) and then fibrillated or fiberized intofilaments. Examples of such processes are described in U.S. Pat. No.4,536,361 to Torobin, U.S. Pat. No. 6,110,588 to Perez et al., U.S. Pat.No. 7,666,343 to Johnson et al., U.S. Pat. No. 6,800,226 to Gerking.Electrospinning processes useful to make fine fibers are described inU.S. Pat. No. 1,975,504 to Formhals et al., U.S. Pat. No. 7,585,437, toJirsak et al., U.S. Pat. No. 6,713,011 to Chu et al., U.S. Pat. No.8,257,641 to Qi et al.; and also in “Electrospinning”, by A. Greiner andJ. Wendorff, in Angew. Chem. Int. Ed., 2007, 46(30), 5670-5703.

The spunlaid or spunbond fibers typically have an average diameter inthe range of about 8 microns to about 30 microns, or a fiber titer inthe range from 0.5 to 10 denier. The meltblown fibers have a diameter oftypically in the range from 0.5 microns to 10 microns on average, or0.001 denier to 0.5 denier, and range from about 0.1 microns to over 10microns. Fine fibers range in average or median diameter from 0.1microns to 2 microns, and some fine fibers have a number-averagediameter of less than about 1 micron, a mass-average diameter of lessthan about 1.5 microns, and a ratio of the mass-average diameter to thenumber-average diameter less than about 2.

Often meltblown nonwoven layers (“M”) are added to spunlaid nonwovenlayers (“S”) to form spunbond-meltblown (“SM”) nonwoven substrates,spunbond-meltblown-spunbond (“SMS”) nonwoven substrates, SSMMS nonwovensubstrates, SSMMSS nonwoven substrates, or other nonwoven substrates,which combine the attributes of S and M nonwoven structures, e.g.,strong nonwoven substrates with some fluid barrier properties. The samecan be done with fine fibers and layers of fine fibers, denominated “N”,to make SN, MN, SMN, SMNS, SMNMS, SNMN, SSMNS, SSMNNS, or other suitablecombinations of layers.

Dry-Laid and Wet-Laid Nonwoven Substrates

In addition to nonwoven substrates made from the fiber spinningtechnologies of molten materials, nonwoven substrates may be made byother means from preformed fibers (including natural fibers), such as bydrylaid or wetlaid technologies. Drylaid technologies include cardingand airlaying. These technologies may be combined with each other, e.g.,drylaid with meltspun, to form multi-layer, functional nonwovensubstrates.

The carding process uses fibers cut into discrete lengths called staplefiber. The type of fiber and the desired end product propertiesdetermine the fiber length and denier. Typical staple fibers have alength in the range of 20 mm to 200 mm and a linear density in the rangeof 1 dpf to 50 dpf (denier per fiber), though staple fibers beyond thisrange have also been used for carding. The carding technology processesthese staple fibers into a formed substrate. Staple fibers are typicallysold in compressed bales that need to be opened to make uniform nonwovensubstrates. This opening process may be done through a combination ofbale opening, coarse opening, fine opening, or by a similar process.Staple fibers are often blended in order to mix different fiber typesand/or to improve uniformity. Fibers may be blended by blending fiberhoppers, bale openers, blending boxes, or by similar methods. The openedand blended fibers are transported to a chute that deposits the fibersacross the width of the card and with a density as uniform as practicalin order to make a nonwoven substrate with the desired basis weightuniformity. The card contains a series of parallel rollers and/or fixedplates that are covered with metallic clothing, rigid saw-toothed wireswith specific geometry that staple fibers are processed between. Cardingtakes place when fiber tufts transport between the tangent points of twosurfaces that have a differential surface speed and opposing angledirections on the metallic clothing. Cards may have a single maincylinder to card with or multiple cylinders. Cards may have a singledoffer or multiple doffers to remove the carded fibers and the cards maycontain randomizing rollers or condenser rollers to reduce the highlyisotropic orientation of the individual fibers in the web. The cardingprocess may contain a single card or multiple cards in line with oneanother, where the fibers of a subsequent card are deposited on top ofthe fibers from a preceding card and thus can form multiple layers,e.g., of different fiber compositions. The orientation of these cardsmay be parallel to the downstream operation or perpendicular to thedownstream operation by means of turning or cross-lapping.

The airlaid process also uses fibers of discrete length, though thesefibers are often shorter than the staple fibers used for carding. Thelength of fibers used in airlaying typically ranges from 2 mm to 20 mm,though lengths beyond this range may also be used. Particles may also bedeposited into the fibrous structure during the airlaying process. Somefibers for airlaying may be prepared similarly as for carding, i.e.,opening and blending as described above. Other fibers, such as pulp, mayuse mills, such as hammer mills or disc mills, to individualize thefibers. The various fibers may be blended to improve the uniformity ofproperties of the finished nonwoven substrate. The airlaying formingdevice combines external air and the fibers and/or particles so that thefibers and/or particles are entrained in the airsteam. Afterentrainment, the fibers and/or particles are collected as a loose webupon a moving foraminous surface, such as a wire mesh conveyor belt, forexample. The airlaying process may contain a single airlaying formingdevice or multiple airlaying forming devices in line with one another,where the fibers and/or particles of the subsequent airlaying formingdevice are deposited on top of the fibers and/or particles from apreceding airlaying forming device, thereby allowing manufacture of amulti-layered nonwoven substrate.

Wet-laid nonwovens are made with a modified papermaking process andtypically use fibers in the range of 2 mm to 20 mm, though lengthsbeyond this range have also been used. Some fibers for wetlaying may beprepared similarly as for carding, i.e., opening and blending asdescribed above. Other fibers, such as pulp, may use mills, such ashammer mills or disc mills, to individualize the fibers. The fibers aresuspended in water, possibly with other additives like bonding agents,and this slurry is typically added to a headbox from where it flows ontoa wetlaid forming device to create a sheet of material. After initialwater removal, the web is bonded and dried.

Bonding

Nonwoven substrates may be bonded (consolidated) by thermal, mechanicalor chemical processes. With nonwoven substrates made from cellulosicmaterials, nonwoven substrates may be hydrogen bonded. Bonding istypically performed in line with the forming process, but may beperformed off line as well. Thermal bonding includes calender bondingwith smooth and/or patterned rolls and thru-air bonding with flat beltand/or drum surfaces. Mechanical bonding includes needlepunching,stitchbonding, and hydroentangling (also known as spunlacing). Chemicalbonding includes adhesive, latex, and/or solvent application to thefibers by spraying, printing, foaming, or saturating, followed by dryingand creating a useful nonwoven substrate of sufficient integrity. Otherpost-processing, like printing or coating, may follow. Afterwards thenonwoven substrates are wound into roll form, slit/rewound, packaged,and shipped for further processing and/or converting into end products.

Composition of Fibers and Filaments

In various embodiments, synthetic fibers of the nonwoven structures maybe made of polyesters, including PET, PTT, PBT, and polylactic acid(PLA), and alkyds, polyolefins, including polypropylene (PP),polyethylene (PE), and polybutylene (PB), olefinic copolymers fromethylene and propylene, elastomeric polymers including thermoplasticpolyurethanes (TPU) and styrenic block-copolymers (linear and radial di-and tri-block copolymers such as various types by Kraton), polystyrenes,polyamides, PHA (polyhydroxyalkanoates) and e.g., PHB(polyhydroxubutyrate), and starch-based compositions includingthermoplastic starch, for example. The constituents of the fibers may bederived from biological sources such as plant matter, such as for PLA or“bio-PE”, for example. The above polymers may be used as homopolymers,copolymers, blends, and alloys thereof. In the various embodiments,natural fibers of the nonwoven structures may be made of, but notlimited to, digested cellulose fibers from softwood (derived fromconiferous trees), hardwood (derived from deciduous trees) or cotton,including rayons and cotton, fibers from Esparto grass, bagasse, kemp,flax, jute, kenaf, sisal, and other lignaceous and cellulose fibersources. The fibers may comprise other constituents for color, strength,aging stability, odor control or other purposes, e.g. titanium-dioxideto reduce gloss and improve opacity.

A variety of mass-produced absorbent articles and articles of commerceemploy nonwoven substrates, such as SMS substrates, in theirmanufacture. One of the largest users of these nonwoven substrates isthe disposable diaper industry, the wipes industry, the cleaningsubstrate industry, and feminine care products industry.

FIG. 1 illustrates a schematic diagram of a forming machine 110 used tomake a nonwoven substrate 112 of the present disclosure. To make anonwoven substrate, the forming machine 110 is shown as having a firstbeam 120 for producing first coarse fibers 135 (e.g., spunbond fibers),an optional second beam 121 for producing intermediate fibers 127 (e.g.,meltblown fibers), a third beam 122 for producing fine fibers 131 (e.g.,N-fibers), and a fourth beam 123 for producing second coarse fibers 124(e.g., spunbond fibers). The forming machine 110 may comprise an endlessforming belt 114 which travels around rollers 116, 118 so the formingbelt 114 is driven in the direction as shown by the arrows 114. Invarious embodiments, if the optional second beam 121 is utilized, it maybe positioned intermediate the first beam 120 and the third beam 122 (asillustrated), or may be positioned intermediate the third beam 122 andthe fourth beam 124, for example. Rolls 138 and 140 may form a nip tobond or calender bond the fibers in the multiple layers together to formthe nonwoven substrate. Element 136 may be a layer of spunbond fibers.Element 128 may be a layer of intermediate fibers, spunbond fibers, orfine fibers. Element 132 may be a layer of intermediate fibers, spunbondfibers, or fine fibers. Element 125 may be a layer of spunbond fibers.Each of the layers of fibers may be formed to grow fibrils extendingoutwardly therefrom after a predetermined period of time under ambientconditions, as discussed in further detail below. FIG. 2 illustrates across-sectional view of an SNS nonwoven substrate or an SMS nonwovensubstrate at a calender bond site 168 in accordance with an embodiment.Fibrils may grow out of the calendar bond site 168 after a predeterminedperiod of time under ambient conditions, as discussed below. Thespunbond, intermediate, and fine fibers may be of single component orbicomponent or polymer blend type.

In an embodiment, referring to FIGS. 5 and 6, the nonwoven substrate 112may comprise a first nonwoven layer 125, a second nonwoven layer 132,and a third nonwoven layer 136. The bond site 168 may have a bond area.The second nonwoven layer 132 may be disposed intermediate the firstnonwoven layer 125 and the third nonwoven layer 136. Also, the firstnonwoven layer 125, the second nonwoven layer 132, and the thirdnonwoven layer 136 may be intermittently bonded to each other using anysuitable bonding process, such as a calendering bonding process, forexample. In an embodiment, the nonwoven substrate 112 does not comprisea film. In various embodiments, the nonwoven substrate 112 may comprisea spunbond layer, which may correspond to the first nonwoven layer 125,an N-fiber layer or intermediate layer, which may correspond to thesecond nonwoven layer 132, and a second spunbond layer, which maycorrespond to the third nonwoven layer 136.

In an embodiment, referring to FIGS. 7 and 8, a nonwoven substrate 212may comprise a first nonwoven layer 225, a second nonwoven layer 232, athird nonwoven layer 236, and a fourth nonwoven layer 228. A bond site268, such as a calender bond site, is illustrated in the nonwovensubstrate 212. The bond site 268 has a bond area. The first nonwovenlayer 225, the second nonwoven layer 232, the third nonwoven layer 236,and the fourth nonwoven layer 228 may be intermittently bonded to eachother using any suitable bonding process, such as a calendering bondingprocess, for example. In an embodiment, the nonwoven substrate 212 doesnot comprise a film. In various embodiments, the nonwoven substrate 212may comprise a spunbond layer, which may correspond to the firstnonwoven layer 225, a meltblown layer or fine fiber layer, which maycorrespond to the fourth nonwoven layer 228, a fine or N-fiber layer ora meltblown layer, which may correspond to the second nonwoven componentlayer 232 and a second spunbond layer, which may correspond to the thirdnonwoven component layer 236. Other configurations of nonwovensubstrates are envisioned and are within the scope of the presentdisclosure, such as a nonwoven substrate comprising one or more spunbondlayers, one or more meltblown or intermediate layers, and/or one or morefine or N-fiber layers, for example.

In an embodiment, the nonwoven substrates of the present disclosure maybe formed of a plurality of nonwoven layers arranged in variouscombinations and permutations of a plurality of spunbond, meltblown, andN-fiber layers, including but not limited to SMS, SMMS, SSMMS, SMMSS,SMN, SNS, SMNMS, SMMNMS, SSMMNS, SSNNSS, SSSNSSS, SSMMNNSS, SSMMNNMS,and the other suitable variations.

In an embodiment, a nonwoven substrate may comprise one or more layersof spunbond fibers “S”, meltblown fibers “M”, and/or fine fibers “N”.One or more of the nonwoven layers may comprise fibers, wherein at leasta plurality of the fibers, or all or most of the fibers, comprisefibrils extending outwardly or largely radially outwardly from a surfaceor a radial outer surface of the fibers. In an embodiment, the fibrilsmay be present in one layer of the nonwoven substrate (in all or some ofthe fibers), in all layers of the nonwoven substrate (in all or some ofthe fibers), or in less than all layers of the nonwoven substrate (inall or some of the fibers). In one instance, at least one layer of thenonwoven substrates of the present disclosure may have a plurality offibers, or all fibers, that are free of fibrils, or substantially freeof fibrils.

Scanning electron microscope photographs of nonwoven substrates havingspunbond fibers comprising fibrils extending outwardly or radiallyoutwardly from a surface thereof are illustrated in FIGS. 10-15. FIGS.6-8 are of a 22 gsm SMMS nonwoven substrate, wherein the spunbond fibersof the nonwoven substrate were formed from a composition comprisingabout 10% of the lipid ester glycerol tristearate by weight of thecomposition. The spunbond layers of the nonwoven substrate each have a10 gsm basis weight, while the meltblown layers each have a 1 gsm basisweight. The meltblown layers in FIGS. 6-8 do not have fibers comprisingfibrils, although the meltblown fibers (and fine fibers) having fibrilsis within the scope of the present disclosure. FIGS. 11 and 12 are moremagnified views of the nonwoven substrate of FIG. 6. FIGS. 9-11 are of a14 gsm SM nonwoven substrate, wherein the spunbond fibers of thenonwoven substrate were formed from a composition comprising 10% of thelipid ester glycerol tristearate by weight of the composition. FIGS. 14and 15 are more magnified views of the nonwoven substrate of FIG. 9. Thespunbond layer of the nonwoven substrate has a basis weight of 13 gsmand the meltblown layer has a basis weight of 1 gsm. The meltblownlayers of FIGS. 9-11 do not have fibers comprising fibrils, although themeltblown fibers (and fine fibers) having fibrils is within the scope ofthe present disclosure.

FIGS. 12-14 illustrate SEM photographs of cross-sectional views of anSMNS nonwoven substrate, wherein at least some of the spunbond fiberscomprise fibrils. The nonwoven substrate has a total basis weight of 18gsm. The spunbond fibers comprising fibrils are formed from acomposition comprising 10% glycerol tristearate, by weight of thecomposition. The meltblown layer and the fine fiber layer do not havefibers comprising fibrils in FIGS. 12-14, although the meltblown andfine fibers having fibrils is within the scope of the presentdisclosure.

Some example configurations of nonwoven substrates having one or morelayers having a plurality of fibers comprising fibrils, or all fiberscomprising fibrils, are listed below. An “*” after the letter indicatesthat the layer has fibers, wherein at least some of, or all of, thefibers have fibrils. Some example configurations are as follows: S*MS*,SM*S, S*M*S, SM*S*, S*M*S*, S*M*NS, S*M*NS*, S*M*N*S*, SM*N*S, S*MNS*,SMN*S, S*SMNS, S*S*MNS, S*S*MNS*, S*S*M*NS*, S*S*M*N*S*, S*SM*NS*,S*MNMS*, S*M*NMS*, SSM*N*MS, S*S*M*MS, S*SM*MS, and/or S*MM*S. Any othersuitable configurations of layers with or without fibrils are alsowithin the scope of the present disclosure.

In some embodiments, it may be desirable for one or more layerscomprising fibers comprising fibrils to be positioned on certain sidesof the nonwoven substrate or at certain locations within the nonwovensubstrate. In an example, the layers comprising the fibers comprisingthe fibrils may be positioned on a wearer-facing side or agarment-facing side or both of an absorbent article while the middlelayers of the nonwoven substrate may or may not comprise fiberscomprising fibrils. In other embodiments, the layers comprising thefibers comprising fibrils may be positioned in intermediate layers ofthe nonwoven substrate. In still other embodiments, the layerscomprising fibers comprising fibrils may alternate through a nonwovensubstrate (e.g., layer with fibers comprising fibrils, layer withoutfibers comprising fibrils, layer with fibers comprising fibrils etc.).In other embodiments, the layers with fibers comprising fibrils may bepositioned in surface to surface contact with each other. Thepositioning of the layers comprising fibers comprising fibrils may bespecific to particular applications. For a wipe, the layer or layers offibers comprising fibrils may be positioned on the side of the wipe thatwill contact the surface or body part to be cleaned, wiped, rubbed, orscrubbed or may be positioned at other locations. While the fibrilsextend outwardly from surfaces of individual fibers, the fibrils mayalso extend to (i.e., contact) other fibers within the same layer or adifferent layer of a nonwoven substrate and/or to fibrils extending fromfibers within the same layer or a different layer of the nonwovensubstrate. An example of this feature is disclosed in FIGS. 14 and 15.When the fibrils extend between fibers and/or other fibrils, thenonwoven substrate may achieve a greater resistance to fluid penetration(e.g., low surface tension fluid strikethrough) owing to the fibrilsclosing gaps or pores in the nonwoven substrate when engaged to otherfibers or fibrils. Stated another way, the fibrils extending between thefibers and/or other fibrils reduce the open area of the nonwovensubstrate, thereby increasing its fluid barrier properties. In someinstance, longer fibrils may contact other fibrils and/or fibers morethan shorter fibrils. In various embodiments, the fibrils may have alength, from an outer surface, or a radial outer surface, of the fibersto a free end of the fibrils (i.e., the end of the fibrils most distalfrom the outer surface of the fibers), in the range of about 0.2 μm toabout 40 μm, about 0.5 μm to about 20 μm, about 1 μm to about 15 μm,about 1 μm to about 10 μm, about 1 μm to about 5 μm, about 2.5 μm toabout 5 μm, about 2 μm to about 4 μm, about 2.5 μm to about 3.5 μm, orabout 3 μm, specifically reciting all 0.1 μm increments within theabove-referenced ranges and all ranges formed therein or thereby. Thefibrils of the various fibers in the one or more nonwoven layers may bethe same length or within the same range of lengths, substantially thesame length or within substantially the same range of lengths, or mayhave different lengths or different ranges of lengths. In an embodiment,the fibers in a layer of a nonwoven substrate, such as a spunbond layer,may have fibers having fibrils with a first length or range of lengthsand the fibers in a second layer of the nonwoven substrate, such asanother spunbond layer, a meltblown layer, or a fine fiber layer, mayhave fibers having fibrils with a second length or range of lengths. Thefirst and second lengths and/or ranges of lengths of the fibrils may bethe same, substantially the same, or different. In an embodiment, thefirst and second lengths and/or ranges of lengths of the fibrils may besmaller or larger in the meltblown layer(s) or fine fiber layer(s) thanin the spunbond layer(s). Furthermore, the first and second lengthsand/or ranges of lengths of the fibrils may be smaller or larger in thefine fiber layer(s) than in the meltblown layer(s). The fibrils may havea uniform thickness or a varying thickness and may have any suitablecross-sectional shape. It is believed that one key factor thatdetermines the length, thickness, and/or cross-sectional shape of thefibrils is the amount, by weight of the composition, of melt additives,such as lipid esters, added to a composition used for forming thefibers, as will be discussed in further detail below. Similarlyimportant is the selection of the bulk polymer composition into whichthe melt additive is inserted and out of which the fibrils emerge, morespecifically, the hardness, density, and crystallinity of the bulkpolymer matrix in the fibers is a factor. Another factor is thecomposition of the melt-additive, e.g., the specific type of lipid estersuch that it can diffuse through the bulk polymer matrix more or lesseasily and such that it can continue to grow as a fibril from surface ofthe fiber. Other factors affecting the length, thickness, and/orcross-sectional shape of the fibrils are environmental conditions,especially conditions significantly above or below ambient conditions.The length of the fibrils is measured according to the Fibril LengthMeasurement Test described below. In various embodiments, the fibrilsmay have a cross-sectional shape that is not circular, but instead isgenerally elliptical or even close to being rectangular. It is thereforeuseful to describe the cross-sectional size (“thickness” or “width”) ofthe fibrils in terms of hydraulic diameter. The hydraulic diameter isdetermined by calculating the cross-sectional area (taken somewhere inthe center ⅓ of the length of the fibril), multiplied by 4, and dividedby the perimeter of the cross-sectional shape. Hydraulic DiameterD_(H)=4*Area/Perimeter. For a fibril having a circular-shapedcross-section, the hydraulic diameter is equal to the diameter of thefibril, and for a fibril having a rectangular-shaped cross-section, thehydraulic diameter, D_(H)=4*L*W/(2*L+2*W) with L and W being therectangular sides of the cross-section, so that a fibril withcross-sectional dimensions of 300 nm (W) and 1500 nm (L) has a hydraulicdiameter of 500 nm. Approximations for perimeters of othercross-sectional shapes can be calculated according to known mathematicalformulas.

In various embodiments, the average hydraulic diameter (i.e.,cross-sectional thickness) of the fibrils may be in the range of about50 nm to about 1100 nm, about 100 nm to about 800 nm, about 200 nm toabout 800 nm, about 300 nm to about 800 nm, about 500 nm to about 800nm, about 100 nm to about 500 nm, or about 600 nm, specifically recitingall 1 nm increments within the above-referenced ranges and all rangesformed therein or thereby. The hydraulic diameter of an individualfibril may be constant, substantially constant or variable about thefibril's length. In an embodiment, the hydraulic diameter of a fibrilmay decrease about the length of the fibril (from the beginning end ofthe fibril to its most distal end). In an embodiment, the fibers in alayer of a nonwoven substrate, such as a spunbond layer, may have fibershaving fibrils with a first average hydraulic diameter or range ofaverage hydraulic diameters and the fibers in a second layer of thenonwoven substrate, such as a meltblown layer or a fine fiber layer, mayhave fibers having fibrils with a second average hydraulic diameter orrange of average hydraulic diameters. The first and second averagehydraulic diameters and/or ranges of average hydraulic diameters of thefibrils may be the same, substantially the same, or different. In anembodiment, the first and second average hydraulic diameters and/orranges of average hydraulic diameters of the fibrils may be smaller,larger, or the same in the meltblown layers or fine fiber layers than inthe spunbond layer or layers. Furthermore, the first and second averagehydraulic diameters and/or ranges of average hydraulic diameters of thefibrils may be smaller, larger, or the same in the fine fiber layersthan in the meltblown layers.

In an embodiment, a nonwoven substrate may have bond sites, like thebond sites 168, 268 described above in reference to FIGS. 5 and 7. Thebond sites may each have a bond area. FIG. 15 illustrates an SEMphotograph at 200 times magnification of fibrils that have grown from aportion of a bond site within the bond area after the bond site wascreated in a nonwoven substrate. This photograph was taken at least 100hours after the bond site (e.g., a calendar bond) was formed in thenonwoven substrate. The nonwoven substrate of FIG. 15 is an SM nonwovensubstrate, wherein the spunbond fibers of the nonwoven substrate wereformed from a composition comprising 10% of the lipid ester glyceroltristearate by weight of the composition. The meltblown layer in FIG. 15does not comprise fibers having fibrils, although the meltblown fibers(and fine fibers) having fibrils is within the scope of the presentdisclosure. The spunbond layer is 13 gsm, while the meltblown layer is 1gsm. The fibrils may extend outwardly from a surface of the bond site.In such an embodiment, the layers of fibers of the nonwoven substratewere formed and then calender bonded or otherwise bonded (e.g., usingthe rolls 138 and 140 of FIG. 1), then the fibrils grew outwardly fromthe surface of the bond site from the fibers in one or more of thelayers of the nonwoven substrate. Packages, packaging materials, andwipes of the present disclosure may also comprise nonwoven substratescomprising a layer of fibers comprising bond sites, wherein each bondsite comprises a bond area, and wherein a plurality of fibrils extendoutwardly from a surface of the bond area.

FIGS. 16-18 are SEM photographs of cross-sectional views taken about aportion of a bond site of an SMNS nonwoven substrate having a basisweight of 18 gsm. The spunbond fibers of the nonwoven substrate areformed from a composition comprising 10% of glycerol tristearate byweight of the composition. At least some of the spunbond fibers comprisefibrils. The meltblown layer and the fine fiber layer do not have fiberscomprising fibrils in FIGS. 16-18, although the meltblown and finefibers having fibrils is within the scope of the present disclosure.

In an embodiment, the composition used to create a layer of fibers,wherein at least some of, or all of, the fibers comprise fibrilsextending outwardly therefrom, may comprise polyolefins and one or moremelt additives, such as lipid ester melt additives, or any of thematerials discussed herein with respect to fibers compositions with themelt additives. The polyolefins may comprise polypropylene,polyethylene, or other polyolefins, such as polybutylene orpolyisobutylene, for example. The melt additives or lipid esters may bepresent in the composition, by weight of the composition, in the rangeof 2% to 45%, 11% to 35%, 11% to 30%, 11% to 25%, 11% to 20%, 11% to18%, 11% to 15%, 11% to 15%, 3%, 5%, 10%, 11%, 12%, 15%, 20%, 25%, 30%,35%, or 40%, specifically reciting all 0.5% increments within theabove-specified ranges and all ranges formed therein or thereby. Themelt additives suitable for the present disclosure may be hydrophobicmelt additives. Thus, the melt additives may increase the hydrophobicityof the fibers in the layers of fibers, especially when the fibrils growout of the fibers. This leads to increased low surface tension fluidstrikethrough times and higher hydrophobicity for the layer of fiberswithin the nonwoven substrates and/or the nonwoven substrates themselveswhen compared to nonwoven substrates not having at least one layerformed from a composition comprising the one or more melt additives.This can also lead to better filtration and/or particular capturingproperties when compared to conventional nonwoven substrates.

The melt additives of the present disclosure, namely the lipid esters,may have a melting point in the range of 30° C. to 160° C., 40° C. to150° C., 50° C. to 140° C., 50° C. to 120° C., 50° C. to 100° C., 60° C.to 80° C., 60° C. to 70° C., about 60° C., about 65° C., or about 70°C., specifically reciting all one degree C. increments within thespecified ranges and all ranges formed therein or thereby. In variousembodiments, the melt additives of the present disclosure may have amelting temperature above 30° C., above 40° C., or above 50° C., butless than 200° C. or less than 150° C.

The melt additives used in the composition may comprise fatty acidderivatives, such as a fatty acid ester; typically an ester formed froman alcohol with two or more hydroxyl groups and one or more fatty acidshaving at least 8 carbon atoms, at least 12 carbon atoms, or at least 14carbon atoms, whereby within one ester compound, different fattyacid-derived groups may be present (herein referred to as fatty acidester).

The fatty acid ester compound may be an ester of an alcohol carrying twoor more, or three or more, functional hydroxyl group per alcoholmolecule, whereby all of the hydroxyl groups form an ester bond withfatty acids (either the fatty acid or mixtures thereof).

In an embodiment, the alcohol may have three functional hydroxyl groups.

In an embodiment, the one or more melt additives may comprise a mono-and/or di-glyceride ester, and/or a triglyceride ester, (with one, twoor three fatty acid-derived groups).

The fatty acids used to form the ester compounds include fatty acidderivatives for the purpose of the present disclosure. A mono-fatty acidester, or for example, amono-glyceride, comprises a single fatty acid,e.g., connected a glycerol; a di-fatty acid ester, or e.g.,di-glyceride, comprises two fatty acids, e.g., connected to theglycerol; a tri-fatty acid ester, or e.g. tri-glyceride, comprises threefatty acids, e.g., connected to a glycerol. In an embodiment, the meltadditive may comprise at least a triglyceride ester of fatty acids(i.e., the same or different fatty acids).

It should be understood that the triglyceride ester may have anesterified glycerol backbone having no nonhydrogen substituents on theglycerol backbone; however, the glycerol backbone may also compriseother substituents.

In an embodiment, the glycerol backbone of the glycerol ester may onlycomprise hydrogen. The glyceride esters may also comprise polymerized(e.g., tri) glyceride esters, such as a polymerized, saturated glycerideesters.

In a fatty acid ester having more than one ester bond, such as in di- ortriglycerides, the fatty acid-derived group may be the same, or they maybe two or even three different fatty acids-derived groups.

The melt additive may comprise a mixture of mono-, di-, and/or tri-fattyacid ester (e.g., mono- di- and/or triglyceride) esters with the samefatty-acid derived group per molecule, and/or with different fattyacid-derived groups.

The fatty acids may originate from vegetable, animal, and/or syntheticsources. Some fatty acids may range from a C8 fatty acid to a C30 fattyacid, or from a C12 fatty acid to a C22 fatty acid. Suitable vegetablefatty acids typically include unsaturated fatty acids such as oleicacid, palmitic acid, linoleic acid, and linolenic acid. The fatty acidmay be arachidec, stearic, palmitic, myristic, myristoleic, oleic,limoleic, linolenic, and/or arachidonic acid.

In another embodiment, a substantially saturated fatty acid may be used,particularly when saturation arises as a result of hydrogenation offatty acid precursor. In an embodiment, a C18 fatty acid, oroctadecanoic acid, or more commonly called stearic acid may be used toform an ester bond of the fatty acid ester herein; stearic acid may bederived from animal fat and oils as well as some vegetable oils. Thestearic acid may also be prepared by hydrogenation of vegetable oils,such as cottonseed oil. The fatty acid ester herein may comprise fattyacids of mixed hydrogenated vegetable oil, such as one having CASregistration number 68334-28-1.

At least one stearic acid, at least two, or three stearic acids areconnected to a glycerol, to form a glycerol tristearate, for the meltadditive herein. A melt additive herein may comprise at least glyceroltristearate.

In an embodiment, the melt additive may comprise a glycerol tristearate(CAS No. 555-43-1), also known by such names as tristearin or1,2,3-Trioctadecanoylglycerol. (In the following, the name glyceroltristearate will be used, and in case of doubt the CAS No., shall beseen as the primary identifier). In an embodiment, the fatty acid esterof the melt additive may have a number-averaged molecular weight rangingfrom 500 to 2000, from 650 to 1200, or from 750 to 1000, specificallyreciting all whole integer increments within the above-specified rangesand any ranges formed therein or thereby.

The melt additive may comprise very little or no halogen atoms; forexample, the melt additive may comprise less than 5 wt. % halogen atoms(by weight of the melt additive), or less than 1 wt. %, or less than 0.1wt. % of the melt additive; the melt additive may be substantiallyhalogen-free.

In an embodiment, the melt additive may be or may comprise a lipid esteror glycerol tristearate. In various embodiments, the fibrils maycomprise, consist of, or consist essentially of (i.e., 51% to 100%, 51%to 99%, 60% to 99%, 70% to 95%, 75% to 95%, 80% to 95%, specificallyincluding all 0.1% increments within the specified ranges and all rangesformed therein or thereby) of the melt additive. The master batch addedto the composition from which the fibers of the present disclosure areformed may be the master batch disclosed in U.S. Pat. No. 8,026,188 toMor.

Once the composition of the melt additive and the polyolefin is used toform a layer of fibers, the layer of fibers may be incorporated into anonwoven substrate, as disclosed as an example in FIG. 1. The nonwovensubstrates having one or more layers of fibers having a plurality of thefibers have fibrils extending therefrom may comprise the melt additivesin the range of 1% to 35% by weight of the nonwoven substrate, dependingon the concentration of the melt additive in the composition used toform the fibers and depending on how many of the layers of fibers of thenonwoven substrate have fibers comprising the melt additive. Otherpossible ranges of melt additives, by weight of the nonwoven substrates,may be 2% to 35%, 5% to 25%, 11% to 35%, 11% to 25%, 11% to 20%, 11% to18%, 11% to 15%, 11%, 12%, 13%, 15%, or 18%, specifically including all0.5% increments within the ranges specified in this paragraph and allranges formed therein or thereby.

In an embodiment, the fibrils may grow out of the fibers post-nonwovensubstrate formation (i.e., after the process illustrated in FIG. 1)under ambient conditions. The fibrils may be noticeable using an SEMafter about 6 hours post-nonwoven substrate formation under ambientconditions. Fibril growth may reach a plateau after about 50 hours, 75hours, 100 hours, 200 hours, or 300 hours post-nonwoven substrateformation under ambient conditions. The time range of noticeable fibrilgrowth post-nonwoven substrate formation may be in the range of 5 hoursto 300 hours, 6 hours to 200 hours, 6 hours to 100 hours, 6 hours to 24hours, 6 hours to 48 hours, or 6 hours to 72 hours, under ambientconditions, specifically reciting all 1 minute increments within theabove specified ranges and all ranges formed therein or thereby. Thetime to allow full fibril growth post-nonwoven substrate formation maybe 12 hours, 24 hours, 48 hours, 60 hours, 72 hours, 100 hours, or 200hours, for example, under ambient conditions.

A method of forming an absorbent article having one or more of thenonwoven substrates of the present disclosure is also provided. Theabsorbent article, as described in the methods, may be a diaper,training pant, adult incontinence product, and/or a sanitary tissueproduct, for example.

In an embodiment, a method of forming an absorbent article may compriseproviding one or more nonwoven substrates each comprising one or morelayers of fibers, wherein a plurality of the fibers, or all of thefibers, in the one or more of the layers comprises a plurality offibrils extending outwardly, or radially outwardly, from a body and/orsurface of the fibers. The fibrils may at least extend outwardly from alongitudinal central third of the fibers. The fibrils may comprise,consist of, or consist essentially of, one or more melt additives, suchas a lipid ester or glycerol tristearate. The method may furthercomprise incorporating the one or more nonwoven substrates into theabsorbent article. In an embodiment, the incorporating comprises formingat least a portion of a filmless liquid impervious material or backsheetof an absorbent article. In other embodiments, the incorporatingcomprises forming at least a portion of a filmless liquid perviousmaterial or topsheet of an absorbent article. In still anotherembodiment, the incorporating comprises forming a portion of a barrierleg cuff or gasketing cuff of an absorbent article or another portion ofthe absorbent article, such as the core cover or dusting layer, forexample.

In an embodiment, a method of forming a component of, or a portion of,an absorbent article, a package, or an article of commerce may compriseforming fibers used to create a first layer of a nonwoven substrate,wherein the fibers in the first layer are formed from a compositioncomprising a thermoplastic polymer and a lipid ester, such as glyceroltristearate. The method may comprise forming fibers used to create asecond layer of the nonwoven substrate. The fibers of the second layermay or may not be formed from a composition comprising a lipid ester,such as glycerol tristearate, but may at least comprise a thermoplasticpolymer. In an embodiment, the first layer may comprise spunbond fibersor meltblown fibers and the second layer may comprise spunbond fibers,meltblown fibers, or fine fibers. The method may further comprisebonding the first and second layers together and growing fibrils from atleast some of the fibers under ambient conditions after a predeterminedtime (e.g., 6 hours to 100 hours or 24 hours to 300 hours) to form thenonwoven substrate. The fibrils may grow at least out of the central ⅓of the longitudinal length of the fibers. The growing fibrils step mayoccur before or after the bonding step. The bonding may be calendarbonding, mechanical bonding, thermal bonding, and/or other bonding typesknown to those of skill in the art. The method may comprise formingfibers used to create at least a third layer (i.e., fourth layer, fifthlayer etc.) of the nonwoven substrate. The fibers of the third layer mayor may not be formed from a composition comprising a lipid ester, suchas glycerol tristearate, but may at least comprise a thermoplasticpolymer. The bonding step may include bonding the first, second, and atleast third layers together to form the nonwoven substrate. The third,fourth, fifth etc. layer may comprise spunbond fibers, meltblown fiber,and/or fine fibers.

In another embodiment, a method of forming a component of an absorbentarticle may comprise the steps of providing one or more nonwovensubstrates each comprising one or more layers of fibers, allowing aplurality of fibrils to grow out of the at least some of, or all of, thefibers post-nonwoven substrate formation under ambient conditions, andincorporating the nonwoven substrate into one or more of the componentsof the absorbent article. The incorporating step may be performed beforeor after the allowing step. The components may be one or more of abarrier leg cuff, a gasketing cuff, a topsheet or liquid perviousmaterial, a backsheet or liquid impervious material, wings, core covers,dusting layers, or other components. The components may be filmless ormay be combined with a film. The time period of fibril growth,post-nonwoven substrate formation, or fiber formation, may be at least12 hours, at least 24 hours, at least 50 hours, at least 75 hours, atleast 100 hours, or at least 200 hours.

In other embodiment, the method of forming an absorbent article maycomprise the steps of providing one or more nonwoven substratescomprising one or more layers of fibers, allowing the nonwoven substrateto increase in specific surface area by at least 10%, 15%, 20%, 25%,100%, 200% or more, but less than 400%, 350% or 300%, from 10% to 350%,or from 20% to 200%, specifically reciting all 1% increments within thespecified ranges and all ranges formed therein or thereby, post-nonwovensubstrate formation under ambient conditions, allowing fibrils to growout of one or more of the layers post-nonwoven substrate formation underambient conditions, and incorporating the nonwoven substrate into aportion of the absorbent article. The incorporating step may beperformed before or after either or both of the allowing steps. Thefibers having the fibrils may be spunbond fibers, meltblown fibers,and/or fine fibers. The time of increase in specific surface areapost-nonwoven substrate formation under ambient conditions may be atleast 6 hours, at least 24 hours, at least 48 hours, at least 60, hours,at least 100 hours, at least 200 hours, but less than 300 hours,specifically reciting all 1 minute increments within the specifiedranges.

In yet another embodiment, a method of forming the absorbent article maycomprise the steps of providing one or more nonwoven substrates eachcomprising one or more layers of fibers, allowing the one or morenonwoven substrates to increase in specific surface area by at least10%, 15%, 20%, 25%, 100%, 200%, or 300% post-fiber formation underambient conditions of the one or more layer of fibers, and incorporatingthe nonwoven substrate into the absorbent article. The incorporatingstep may occur before or after the allowing step.

In an embodiment, the nonwoven substrates of the present disclosure maycomprise one or more layers of fibers comprising fibrils. The nonwovensubstrates, post-fibril growth under ambient conditions, may havespecific surface areas in the range of 0.3 m²/g to 7 m²/g, 0.5 m²/g to 5m²/g, 0.6 m²/g to 3.5 m²/g, 0.7 m²/g to 3 m²/g, 0.7 m²/g to 1.5 m²/g,0.84 m²/g to 3.5 m²/g, or above 1.15 m²/g, specifically including all0.1 m²/g increments within the above-specified ranges and all rangesformed therein or thereby.

FIG. 19 illustrates a graph of specific surface areas of conventionalnonwoven substrates (various SM and SMN samples without a lipid estermelt additive of the present disclosure) compared to specific surfaceareas of the same nonwoven substrates the lipid ester melt additiveaccording to the present disclosure. The X axis in the figure representsthe specific surface area without the fibrils and the Y axis in thefigure represents the specific surface area with the fibrils. Thenonwoven substrates of the present disclosure of FIG. 19 are formed froma composition comprising 10% (triangles in the figures) or 15% (circlesin the figure) glycerol tristearate by weight of the composition in thespunbond layer of the samples, while the conventional nonwovensubstrates (diamonds in the figure) do not have any glycerol tristearatein their fiber compositions. The dotted line represents the specificsurface areas of the conventional nonwoven substrates. The calculatedspecific surface areas of the conventional nonwoven substrates withoutglycerol tristearate are illustrated as hollow rectangles in the figure.As will be seen, the specific surface areas of the nonwoven substratesof the present disclosure comprising fibers formed from a compositionhaving 10% or 15% glycerol tristearate, by weight of the composition ofthe spunlaid fibers, are much higher than specific surface areas ofconventional nonwoven substrates not having the glycerol tristearate intheir fiber compositions. The asterisks in the figure represent samplesof SMN nonwoven substrates with 1 gsm M and 1 gsm N each and a 13 gsm(lower values in the chart, about 0.67) or 19 gsm (higher values in thechart) spunbond layer having 10-15% glycerol tristearate, by weight ofthe composition used to form the spunbond fibers. These samples have notbeen produced without the melt additive of the present disclosure andare shown to be in the expected, predicted range of specific surfaceareas which are 20% to 100% higher than the samples would be without themelt additive. In an embodiment, the nonwoven substrates of the presentdisclosure may have a low surface tension fluid strikethrough time(according to the LOW SURFACE TENSION FLUID STRIKETHROUGH TIME TESTbelow) to basis weight (according to the BASIS WEIGHT TEST below) ratioof 0.35 s/gsm to 5.0 s/gsm, 0.37 s/gsm to 5.0 s/gsm, 0.4 s/gsm to 4s/gsm, 0.35 s/gsm to 15 s/gsm, 0.5 s/gsm to 15 s/gsm, 1 s/gsm to 10s/gsm, 2 s/gsm to 4 s/gsm, above 0.37 s/gsm, above 0.38 s/gsm, or above0.4 s/gsm, specifically reciting all 0.1 s/gsm increments within theabove specified ranges and all ranges formed therein or thereby. Thisratio may be higher when more lipid ester melt additive is present in anonwoven substrate and lower when less lipid ester melt additive ispresent in a nonwoven substrate.

FIG. 20 illustrates a graph of low surface tension fluid strikethroughtime (seconds) to basis weight (gsm) ratio (seconds/gsm) compared to thebasis weight (gsm) of glycerol tristearate within the nonwovensubstrates. The diamonds represent SM or SMS nonwoven substrates and therectangles represent SMNS and SMN nonwoven substrates. The samplesindicated by diamonds have the same basis weight for both the SM and SMSnonwoven substrate samples. The samples indicated by rectangles have thesame basis weight for both the SMNS and SMS nonwoven substrate samples.The X-axis in the figure represents the glycerol tristearate basisweight in the nonwoven substrates tested. The Y-axis in the figurerepresents the low surface tension fluid strikethrough time (seconds) tobasis weight (gsm) ratio (seconds/gsm) of the nonwoven substratestested. There is at least a 30% change in the strikethrough to basisweight ratio for about every 0.5 gsm of glycerol tristearate within thenonwoven substrates. In some instances, there is about a 100% change inthe strikethrough to basis weight ratio for every 1 gsm of glyceroltristearate within the nonwoven substrates.

In an embodiment, an absorbent article may comprise a nonwoven substratecomprising one or more layers of fibers. The fibers may or may notcomprise fibrils extending outwardly from a surface of the fibers. Thenonwoven substrate may increase in specific surface area by at least 5%,at least 10%, at least 15%, at least 20%, at least 25%, at least 50%, atleast 100%, at least 200%, at least 300%, or in the ranges of 10% to300%, 10% to 250%, or 20% to 200%, specifically reciting all 0.5%increments within the specified ranges and any ranges formed therein orthereby, over a predetermined time period post-nonwoven substrateformation under ambient conditions. The predetermined time period may begreater than 6 hours and less than 200 hours or greater than 12 hoursand less than 120 hours. The predetermined time period post-nonwovensubstrate formation may also be the same as stated herein.

While not intending to be bound by any particular theory, FIG. 21illustrates an example graph of the specific surface area (m²/g) of anonwoven substrate of the present disclosure having 15% glyceroltristearate, by weight of the composition used to produce the spunbondfibers, increasing over time. No glycerol tristearate is present in themeltblown or fine fibers in this example. The nonwoven substrategraphically illustrated in FIG. 21 is a 13 gsm SMN nonwoven substrate.The specific surface area increases post-fiber formation and/orpost-nonwoven substrate formation under ambient conditions.

Referring to FIG. 22, low surface tension fluid liquid strikethroughtimes (seconds) are graphed for various nonwoven substrates of thepresent disclosure. All of the nonwoven substrates of the presentdisclosure are 13 gsm SMN nonwoven substrates. An asterisk refers to alayer with GTS in the layer. The asterisk after the S layer indicatesthat the spunbond fibers having fibrils were formed from a compositioncomprising about 10% GTS, by weight of the composition, while theasterisk after the N layer indicates that the nanofibers were formedfrom a composition comprising about 1% GTS, by weight of thecomposition. As can be seen from FIG. 22, the more layers comprisingglycerol tristearate and thereby fibrils, the higher the low surfacetension strikethrough time will be. The strikethrough times for aconventional 13 gsm SMN nonwoven substrate is also graphicallyillustrated in FIG. 22 for comparison.

Referring to FIG. 23, the low surface tension fluid strikethrough timein seconds (Y-axis) increases in the nonwoven substrates of the presentdisclosure as the glycerol tristearate percent, by weight of thecomposition used to form the fibers, increases. The samples of FIG. 23are 50 gsm spunbond substrates having about 20 micrometer fibers.

Referring to FIG. 24, the low surface tension fluid strikethrough timein seconds (Y-axis) increases in the nonwoven substrates of the presentdisclosure as the glycerol tristearate percent, by weight of thecomposition used to form the fibers (X-axis), and the basis weight ofthe nonwoven substrate increases. The samples of FIG. 24 illustrate aspunbond nonwoven substrate having a basis weight of 13 gsm (bottom linein the figure), a spunbond nonwoven substrate having a basis weight of16 gsm (middle line in the figure), and a spunbond nonwoven substratehaving a basis weight of 19 gsm (top line in the figure). As can be seenin the graph of FIG. 24, the strikethrough time goes up significantly asthe % glycerol tristearate, by weight of the composition used to formthe fibers increases, and as the basis weight of the nonwoven substrateincreases.

Referring to FIG. 25, the low surface tension fluid strikethrough timein seconds (Y-axis) of the nonwoven substrates of the present disclosuredecreases as the fiber diameter increases. All samples have 15% glyceroltristearate, by weight of the composition used to form the fibers. Thesamples of FIG. 25 are 50 gsm spunbond substrates.

Referring to FIG. 26, the low surface tension fluid strikethrough timein seconds (Y-axis) of the nonwoven substrates of the present disclosureincreases as more fine fibers are added to the nonwoven substratesand/or as the basis weight of the glycerol tristearate within thenonwoven substrate increases (X-axis). The top line in the graph is froma nonwoven substrate (SMN) having spunbond/meltblown fibers formed froma composition having 10% glycerol tristearate, by weight of thecomposition, and 1 gsm of fine fibers not having any glyceroltristearate. The bottom line in the graph is from a nonwoven substratehaving spunbond/meltblown fibers formed from a composition having 10%glycerol tristearate, by weight of the composition, and no fine fibers(SM). The top line has 1 gsm extra of basis weight compared to thebottom line owing to the addition of the 1 gsm of fine fibers.

In an embodiment, the nonwoven substrates of the present disclosure maycomprise one or more layers each comprising a plurality of fibers,wherein at least some of the fibers, or all of the fibers, comprisefibrils extending outwardly or radially outwardly from a surfacethereof. The nonwoven substrates may be used as a receiving component inan absorbent article fastening system. The receiving component may beconfigured to receiving a fastening tab of the fastening system 70 oranother fastening tab or member. In an embodiment, the nonwovensubstrate may form all of, or a portion of, a nonwoven landing zone forone or more fastening tabs or members. The fastening tabs or members mayhave hooks (e.g., a side of a hook and loop fastener) that engages thenonwoven substrate. Owing to the specific surface area increase in thenonwoven substrates post-nonwoven substrate formation compared toconventional nonwoven substrates and because of the fibrils, thenonwoven substrates of the present disclosure may provide betterattachment of the hooks to the nonwoven substrates. Example suitablenonwoven landing zone bonding patterns and other considerations for thenonwoven substrates of the present disclosure may be found in U.S. Pat.No. 7,895,718 to Horn et al., U.S. Pat. No. 7,789,870 to Horn et al. andU.S. patent application Ser. No. 13/538,140 to Ashraf et al., Ser. No.13/538,177 to Ashraf et al., and Ser. No. 13/538,178 to Rane et al.

When used as a fluid permeable layer (e.g., topsheet), the nonwovensubstrates of the present disclosure may tend to retain fluid, runningBM, or menses less than conventional nonwoven substrates and thus maydrain more completely to the underlying absorbent core, thereby leavinga more clean-looking and clean-feeling topsheet. Example nonwovensubstrates that may be used as fluid permeable layers may be unaperturedlow density structures, such as a spunlaid structures with relativelyhigh caliper and porosity, or apertured nonwoven substrates.

The nonwoven substrates of the present disclosure having at least onelayer comprising fibers comprising fibrils may be configured to besofter or harder than, or have the same softness as, conventionalnonwoven substrates and/or may have a rougher, smoother, or the sametactile property as compared to conventional nonwoven substrates. Thesoftness, hardness, and/or tactile property of the nonwoven substratesmay vary depending on the type and amount of lipid esters present in thecomposition used to form the fibers and the length of the fibrils, forexample. The softness, hardness, and/or texture may also vary dependingon where the one or more layers of fibers having fibrils are positionedwithin a nonwoven substrate.

In an embodiment, one or more of the nonwoven substrates of the presentdisclosure may be used as a filtration media, a filter, or portionthereof, for various fluids (i.e., liquids (e.g., water) or gases (e.g.,air)). The fibrils, and thereby the increased surface area of thefibers, may allow for better and/or more efficient filtration of thefluids by filtering out more particulate or undesirable materials in thefluids. This may increase the effective lifetime of the filter and/orfiltration media as well. The concentration of the lipid esters byweight of the composition used to make the fibers may be increased tofurther promote more efficient filtration and/or lifetime of the filterand/or filtration media.

In an embodiment, the fibrils may have a different color than the fibersfrom which they grow. Stated another way, the fibrils may have a firstcolor and the fibers from which they grow may have a second color innon-fibril areas of the fibers. The first color may be different thanthe second color (e.g., the fibers in non-fibril areas may be white andthe fibrils may be blue or the fibers in non-fibril areas may be lightblue and the fibrils may be dark blue). This color variation can beaccomplished by adding a colorant, such as a pigment or dye to the lipidesters before they are mixed into the composition used to form thefibers. When the lipid esters grow from the fibers, they will be adifferent color than the fibers from which they grow, thereby producinga color contrast between the fibrils and the fibers from which theygrow. In an embodiment, the layer of nonwoven substrate comprising thefibers comprising the fibrils may appear to change color over a periodof time (i.e., the period of time in which the fibrils grow or a portionthereof) due to the contrasting color of the fibrils with respect to thefibers from which they grow. Different layers of fibers may havedifferent colored fibrils and/or fiber therein within the same nonwovensubstrate. In an embodiment, the colorant added to the lipid esters maybe dissolvable in urine, menses, runny BM, other bodily fluid, or otherfluid (e.g., water). In various embodiments, the dissolving colorant inthe fibrils may be used as a wetness indicator in an absorbent article,for example. The fibers having colors different than their fibrils maybe used in wipes or any portion of an article of commerce, such as anabsorbent article.

The nonwoven substrates of the present disclosure may be used to form atleast a portion of, or all of, any suitable article of commerce. Examplearticles of commerce are wet wipes, baby wet wipes, dry wipes, facialwipes, make-up removal/application wipes, medical wipes, bandages, andwraps, scrubbing wipes, shop towels, towels, cleaning wipes, sanitarywipes, cleaning substrates. The wipes may benefit from the fibrilswithin at least one layer of fibers of the nonwoven substrates becauseof the better absorbency, scrubbing ability, particulate capture,particulate retention, dirt attraction, dirt retention, and/orapplication ability, for example, as a result of the fibrils. Thefibrils may be formed of lipid esters or other melt additives which mayhave a wax-like feel or texture that can be helpful in attracting andretaining dirt particles and other matter.

The wipes, or the one or more nonwoven substrates having fibrils of thewipes, may comprise a composition. The composition may be applied to thefibers of the nonwoven substrate and/or may be at least partiallycomprised in or applied to the fibrils. The composition may comprisewater, a fragrance, a soap, a makeup, a skin care composition, a lotion,a polish, a cleaning composition, other suitable compositions, and/orcombinations thereof. The compositions may be in liquid, semi-liquid,paste, or solid form on the fibrils and/or when applied to the fibrils.In the event that the composition comprises moisture, such as water, thewipe may have 100% to 600%, 150% to 550%, or 200% to 500% weight ofmoisture relative to the dry weight of the wipe or relative to the dryweight of the nonwoven substrate within the wipe, specifically recitingall 1% increments within the above-specified ranges and any rangesformed therein or thereby. The wipe or the nonwoven substrate may haveat least 10%, 20%, 30%, 40%, 50%, 75%, 100%, 150%, 200%, 300% or more ofweight of the composition relative to the total weight of the wipe orrelative to the total weight of the nonwoven substrate. Withoutintending to be bound by any theory, it is believed that nonwovensubstrates having one or more layers of fibers comprising fibrils have abetter affinity to compositions and/or a better ability to retaincompositions to the nonwoven substrate. Therefore, it is believed thatthe fibrils and the nonwoven layer comprising the fibrils may absorb andstably retain higher amounts of compositions as compared to conventionalnonwoven substrates not having fibrils. Furthermore, the fibrils mayinhibit stratification in a stack of multiple wipes during storage andbefore use (i.e., inhibiting dryer wipes on the top of the stack andwetter wipes on the bottom of the stack) better than conventionalnonwoven substrates without fibrils.

In an embodiment, at least some of the fibrils comprising thecomposition may be removable or separatable from the fibers when thewipe is rubbed against a surface, such as a surface to be cleaned or abodily surface. The fibrils may separate from the fibers therebyapplying the composition to the surface. Such separation may occur owingto frictional forces applied to the wipe when moved over the surface. Inan example embodiment, the fibrils comprising the composition may beformed in a skin lotion applying wipe. When a user moves the wipe over abodily surface, the fibrils may separate from the fibers to apply theskin lotion to the bodily surface. Other examples are also within thepresent disclosure.

In an embodiment, the nonwoven substrates of the present disclosurecomprising one or more layers comprising fibers comprising fibrils mayincrease the acoustic dampening properties of the nonwoven substrates,compared to conventional nonwoven substrates, because of the fibrilscausing an increase in the scattering of sounds waves as they passthrough the nonwoven substrate. Further, the nonwoven substrates of thepresent disclosure may have better masking or opacity properties thanconventional nonwoven substrates because of the scattering of lightwaves caused by the fibrils as light waves pass through the nonwovensubstrates.

The nonwoven substrates of the present disclosure may be used aspackaging materials or may be used to form at least portions of, or allof, packages. The packages may take on any suitable configuration, suchas the configuration of one or more articles of commerce within thepackages or any other configuration. Packaging materials, as usedherein, also encompasses release liners that cover adhesives on sanitarynapkins or absorbent articles or any other component placed on, attachedto, or formed with a consumer product prior to sale or use even if thatcomponent does not form an outer portion of a package. In an embodiment,the nonwoven substrates may be used to form at least an outer portion,inner portion, or other portion of the packages. Referring to FIG. 27,the packages 300 may comprise one or more articles of commerce 302 andmay be at least partially formed by the nonwoven substrates 304 of thepresent disclosure. The articles of commerce 302 may also have packagingmaterials formed from the nonwoven substrates of the present disclosure.A portion of the package 300 is cut away in FIG. 27 to illustrateexample articles of commerce 302 within the package 300. The hydrophobicnature and high low surface tension fluid strikethrough times of thenonwoven substrates of the present disclosure provides them with goodresistance to moisture infiltration into the packages, therebymaintaining the articles of commerce in a dry, or substantially drystate, while also providing some breathability to the packages. Thenonwoven substrates may also be combined with other materials, such asfilms, to form packages or packaging materials. One typical packagingmaterial for articles of commerce is films. The nonwoven substrates ofthe present disclosure may be free of films or use less films, therebysaving costs. The nonwoven substrates may also provide softer packagingmaterials than films.

In an embodiment, the lipid esters in the fibers having fibrils of thenonwoven substrates of the present disclosure may be free of droplets oflipid esters. “Free of droplets of lipid esters” means that the lipidester (e.g., GTS) is substantially homogeneously, or homogeneously,distributed throughout the composition used to form the fibers in veryfine particles (i.e., less than 300 nm, less than 200 nm, or less than100 nm) and, thereby, throughout the fibers formed from the composition,and does not form pockets of lipid esters in the fibers. Incross-sections of fibers comprising lipid esters of the presentdisclosure, droplets cannot be seen at 8000 times magnification using anSEM (see e.g., FIG. 34 at 8,000 times magnification). Droplets, as usedherein, have a minimum dimension of at least 300 nm and can be seen inSEMS cross-sections of a fiber at 8,000 times magnification, if present.Further, the fibers, once the lipid ester is dissolved using theGravimetric Weight Loss Test set forth below, do not have void volumesleft therein. Void volumes, as used herein, have a minimum dimension of300 nm and can be seen at 8,000 times magnification of a fiber using aSEM. The fibers of the present disclosure do not have such droplets and,therefore, void volumes are not formed in the fibers post GravimetricWeight Loss Test performance.

FIGS. 33 and 34 show cross-sectional views of fibers post-GravimetricWeight Loss Test performance (e.g., after the lipid esters, such as GTS,in the fibers have been dissolved). The fibers in FIGS. 33 and 34 are ofan 18 gsm SMNS material with about 10% glycerol tristearate, by weightof the composition used to form the S layers, wherein the M layer plusthe N layer has a 2 gsm basis weight, after the GTS has been dissolved.As illustrated, no void volumes are present in the fibers owing to thesubstantially homogeneous, or homogeneous, distribution of the lipidesters within the fibers. Void volumes would have been created in thefibers if the fibers had droplets of lipid esters present therein. Sincethe fibers of the present disclosure are droplet-free, no void volumesare present in the fibers post-Gravimetric Weight Lost Test performance.

Components of the absorbent articles, packages, and articles of commercedescribed herein can at least partially be comprised of bio-sourcedcontent as described in U.S. Pat. Publ. No. 2007/0219521A1 to Hird etal. published on Sep. 20, 2007, U.S. Pat. Publ. No. 2011/0139658A1 toHird et al. published on Jun. 16, 2011, U.S. Pat. Publ. No.2011/0139657A1 to Hird et al published on Jun. 16, 2011, U.S. Pat. Publ.No. 2011/0152812A1 to Hird et al. published on Jun. 23, 2011, U.S. Pat.Publ. No. 2011/0139662A1 to Hird et al. published on Jun. 16, 2011, andU.S. Pat. Publ. No. 2011/0139659A1 to Hird et al. published on Jun. 16,2011. These components include, but are not limited to, topsheetnonwovens, backsheet films, backsheet nonwovens, side panel nonwovens,barrier leg cuff nonwovens, super absorbents, nonwoven acquisitionlayers, core wrap nonwovens, adhesives, fastener hooks, and fastenerlanding zone nonwovens and film bases. In an embodiment, a disposableabsorbent article component, an article of commerce component, or apackage component may comprise a bio-based content value from about 10%to about 100% using ASTM D6866-10, method B, in another embodiment, fromabout 25% to about 75%, and in another embodiment, from about 50% toabout 60% using ASTM D6866-10, method B.

In order to apply the methodology of ASTM D6866-10 to determine thebio-based content of any absorbent article component, package component,or article of commerce component, a representative sample of theabsorbent article component, the package component, or the article ofcommerce component must be obtained for testing. In an embodiment, theabsorbent article component, the package component, or the article ofcommerce component may be ground into particulates less than about 20mesh using known grinding methods (e.g., Wiley® mill), and arepresentative sample of suitable mass taken from the randomly mixedparticles.

FIG. 30 illustrates an example graph of mass-average fiber diameter(X-axis) vs. specific surface area (Y-axis). The triangles represent thecalculated theoretical specific surface area of various S, SM, SMS,SMNS, and M nonwoven substrate samples without the presence of GTS infibers thereof. The “Xs” represent the calculated theoretical specificsurface area of the nonwoven substrate samples at the triangles plus acalculated 20% increase in the specific surface area. This 20% increasein the specific surface area represents the spunbond fibers being formedfrom a composition comprising about 10% to about 15% GTS by weight ofthe composition. If the fibers have a mass-average fiber diameter ofless than 5, the about 10% to about 15% GTS would be added to themeltblown layer since those samples would not have a spunbond layer. Thediamonds represent samples of various SMN nonwoven substrates havingfibers, wherein some of the fibers were formed from compositionscomprising GTS. The S layers were formed from a composition comprisingabout 10% to about 15% GTS, by weight of the composition, and one of theM or N layers were formed from a composition comprising 1% GTS by weightof the composition. The squares represent various samples of SMNnonwoven substrates without any GTS in any of the fibers thereof.Mass-average fiber diameter is set forth in μm and specific surface areais set forth in m²/g. For a mass-average fiber diameter of above 8 um,the specific surface area may be about 1.6 m²/g or more. For amass-average fiber diameter of above 10 um, the specific surface areamay be about 1.2 m²/g or more. For a mass-average fiber diameter ofabove 12 um, the specific surface area may be about 0.8 m²/g or more. Invarious embodiments, the specific surface area of the fibers of thepresent disclosure may be in the range of about 0.5 m²/g to about 10.0m²/g, about 0.7 m²/g to about 8.0 m²/g, or even about 0.8 m²/g to about6.0 m²/g, specifically reciting all 0.1 m²/g increments within thespecified ranges and all ranges formed therein or thereby.

In an embodiment, an absorbent article, a packaging material, and/or awipe may comprise a one or more nonwoven substrates, each comprising aplurality of fibers, wherein at least some of the fibers may have amass-average fiber diameter above 8 μm and a specific surface area of atleast 1.6 m²/g. In an embodiment, an absorbent article, a packagingmaterial, and/or a wipe may comprise a one or more nonwoven substrates,each comprising a plurality of fibers, wherein at least some of thefibers may have a mass-average fiber diameter above 10 μm and a specificsurface area of at least 1.2 m²/g. In an embodiment, an absorbentarticle, a packaging material, and/or a wipe may comprise one or morenonwoven substrates, each comprising a plurality of fibers, wherein atleast some of the fibers may have a mass-average fiber diameter above 12μm and a specific surface area of at least 0.8 m²/g. The absorbentarticles may comprise a liquid pervious material, a liquid imperviousmaterial, and an absorbent core disposed at least partially intermediatethe liquid pervious material and the liquid impervious material.

In an embodiment, an absorbent article may comprise a liquid perviousmaterial, a liquid impervious material, and an absorbent core disposedat least partially intermediate the liquid pervious material and theliquid impervious material. The absorbent article may further comprise anonwoven substrate comprising one or more layers of fibers. A pluralityof the fibers may each comprise a plurality of fibrils extendingoutwardly from a surface of the fibers. The plurality of fibrils maycomprise a lipid ester. A portion of, or all of, the liquid imperviousmaterial may comprise the nonwoven substrate and the liquid imperviousmaterial may be free of a film. A portion of, or all of, the liquidpervious material may comprise the nonwoven substrate and may be free ofa film. The absorbent article may comprise a one or more barrier legcuffs. A portion, or all of, the one or more barrier leg cuffs maycomprise the nonwoven substrate and the barrier leg cuffs, or portionsthereof, may be free of a film. The plurality of fibrils may compriseglycerol tristearate. The glycerol tristearate may have a meltingtemperature above 35° C. or may be in the range of 40° C. to 150° C. Theplurality of fibers may be formed from a composition comprising apolyolefin and the lipid ester. The composition may comprise at least11% of the lipid ester, by weight of the composition. The average lengthof the fibrils from the surfaces of the fibers to free ends of thefibrils may be in the range of 0.5 μm to 20 μm. The average hydraulicdiameter of the fibrils may be in the range of 100 nm to 800 nm. Thelayer of fibers may comprise spunbond fibers, meltblown fibers, and/orfine fibers. At least some of the fibrils may extend radially outwardlyfrom the surface of the fibers in a central longitudinal third of atleast some of the fibers. The fibers comprising the plurality of fibrilsmay be free of droplets of the lipid ester. The layer of fibers maycomprise a plurality of bonds with each bond comprising a bond area. Atleast some of the plurality of fibrils may extend outwardly from asurface of at least one of the bond areas. The nonwoven substrate maycomprise a second layer of fibers. The fibers of the second layer offibers may be substantially free of, or free of, fibrils or may comprisea plurality of fibrils. In an example, the layer of fibers may comprisespunbond fibers and/or meltblown fibers and the second layer of fibersmay comprise meltblown fibers and/or fine fibers. The fibrils may be afirst color (e.g., blue, yellow) and the plurality of fibers may be asecond color (e.g., light blue, green, red, teal) in non-fibril areas ofthe fibers. The first color and the second color may be the same ordifferent.

Tests

Surface Tension of a Liquid

The surface tension of a liquid is determined by measuring the forceexerted on a platinum Wilhelmy plate at the air-liquid interface. AKruss tensionmeter K11 or equivalent is used. (Available by Kruss USA(www.kruss.de)). The test is operated in a laboratory environment at23±2° C. and 50±5% relative humidity. The test liquid is placed into thecontainer given by the manufacturer and the surface tension is recordedby the instrument and its software.

Basis Weight Test

A 9.00 cm² large piece of nonwoven substrate, i.e., 1.0 cm wide by 9.0cm long, is used. The sample may be cut out of a consumer product, suchas a wipe or an absorbent article or a packaging material therefor. Thesample needs to be dry and free from other materials like glue or dust.Samples are conditioned at 23° Celsius (±2° C.) and at a relativehumidity of about 50% (±5%) for 2 hours to reach equilibrium. The weightof the cut nonwoven substrate is measured on a scale with accuracy to0.0001 g. The resulting mass is divided by the specimen area to give aresult in g/m² (gsm). Repeat the same procedure for at least 20specimens from 20 identical consumer products or packaging materialstherefor. If the consumer product or packaging materials therefor arelarge enough, more than one specimen can be obtained from each. Anexample of a sample is a portion of a topsheet of an absorbent article.If the local basis weight variation test is done, those same samples anddata are used for calculating and reporting the average basis weight.

Fiber Diameter and Denier Test

The diameter of fibers in a sample of a nonwoven substrate is determinedby using a Scanning Electron Microscope (SEM) and image analysissoftware. A magnification of 500 to 10,000 times is chosen such that thefibers are suitably enlarged for measurement. The samples are sputteredwith gold or a palladium compound to avoid electric charging andvibrations of the fibers in the electron beam. A manual procedure fordetermining the fiber diameters is used. Using a mouse and a cursortool, the edge of a randomly selected fiber is sought and then measuredacross its width (i.e., perpendicular to fiber direction at that point)to the other edge of the fiber. For non-circular fibers, the area of thecross-section is measured using the image analysis software. Theeffective diameter is then calculated by calculating the diameter as ifthe found area was that of a circle. A scaled and calibrated imageanalysis tool provides the scaling to get actual reading in micrometers(μm). Several fibers are thus randomly selected across the sample of thenonwoven substrate using the SEM. At least two specimens from thenonwoven substrate are cut and tested in this manner. Altogether, atleast 100 such measurements are made and then all data is recorded forstatistical analysis. The recorded data is used to calculate average(mean) of the fiber diameters, standard deviation of the fiberdiameters, and median of the fiber diameters. Another useful statisticis the calculation of the amount of the population of fibers that isbelow a certain upper limit. To determine this statistic, the softwareis programmed to count how many results of the fiber diameters are belowan upper limit and that count (divided by total number of data andmultiplied by 100%) is reported in percent as percent below the upperlimit, such as percent below 1 micrometer diameter or %-submicron, forexample.

If the results are to be reported in denier, then the followingcalculations are made.

Fiber Diameter in denier=Cross-sectional area (in m²)*density (inkg/m³)*9000 m*1000 g/kg.

The cross-sectional area is □*diameter²/4. The density forpolypropylene, for example, may be taken as 910 kg/m³.

Given the fiber diameter in denier, the physical circular fiber diameterin meters (or micrometers) is calculated from these relationships andvice versa. We denote the measured diameter (in microns) of anindividual circular fiber as d_(i).

In case the fibers have non-circular cross-sections, the measurement ofthe fiber diameter is determined as and set equal to the hydraulicdiameter, as discussed above.

Low Surface Tension Fluid Strikethrough Time Test

The low surface tension fluid strikethrough time test is used todetermine the amount of time it takes a specified quantity of a lowsurface tension fluid, discharged at a prescribed rate, to fullypenetrate a sample of a nonwoven substrate that is placed on a referenceabsorbent pad. As a default, this is also called the 32 mN/m Low SurfaceTension Fluid Strikethrough Test because of the surface tension of thetest fluid and each test is done on two layers of the nonwoven substratesample simply laid on top of each other.

For this test, the reference absorbent pad is 5 plies of Ahlstrom grade989 filter paper (10 cm×10 cm) and the test fluid is a 32 mN/m lowsurface tension fluid.

Scope

This test is designed to characterize the low surface tension fluidstrikethrough performance (in seconds) of nonwoven substrates intendedto provide a barrier to low surface tension fluids, such as mixtures ofurine and bowel movements or runny bowel movements for example.

Equipment

Lister Strikethrough Tester: The instrumentation is the same as thatdescribed in EDANA ERT 153.0-02 section 6 with the following exception:the strike-through plate has a star-shaped orifice of 3 slots angled at60 degrees with the narrow slots having a 10.0 mm length and a 1.2 mmslot width. The orifice 2000 is illustrated in FIG. 31. This equipmentis available from Lenzing Instruments (Austria) and from W. FritzMetzger Corp (USA). The unit needs to be set up such that it does nottime out after 100 seconds.

Reference Absorbent Pad: Ahlstrom Grade 989 filter paper, in 10 cm×10 cmareas, is used. The average strikethrough time is 3.3+0.5 seconds for 5plies of filter paper using the 32 mN/m test fluid and without the websample. The filter paper may be purchased from Empirical ManufacturingCompany, Inc. (EMC) 7616 Reinhold Drive Cincinnati, Ohio 45237.

Test Fluid The 32 mN/m surface tension fluid is prepared with distilledwater and 0.42+/−0.001 g/liter Triton-X 100. All fluids are kept atambient conditions. Electrode-Rinsing Liquid: 0.9% sodium chloride (CAS7647-14-5) aqueous solution (9 g NaCl per 1 L of distilled water) isused.

Test Procedure

-   -   Ensure that the surface tension is 32 mN/m+/−1 mN/m according to        the Surface Tension of a Liquid test described herein. Otherwise        remake the test fluid.    -   Prepare the 0.9% NaCl aqueous electrode rinsing liquid.    -   Ensure that the strikethrough target (3.3+/−0.5 seconds) for the        Reference Absorbent Pad is met by testing 5 plies with the 32        mN/m test fluid as follows:    -   Neatly stack 5 plies of the Reference Absorbent Pad onto the        base plate of the strikethrough tester.    -   Place the strikethrough plate over the 5 plies and ensure that        the center of the plate is over the center of the paper. Center        this assembly under the dispensing funnel.    -   Ensure that the upper assembly of the strikethrough tester is        lowered to the pre-set stop point.    -   Ensure that the electrodes are connected to the timer.    -   Turn the strikethrough tester “on” and zero the timer.    -   Using the 5 mL fixed volume pipette and tip, dispense 5 mL of        the 32 mN/m test fluid into the funnel.    -   Open the magnetic valve of the funnel (by depressing a button on        the unit, for example) to discharge the 5 mL of test fluid. The        initial flow of the fluid will complete the electrical circuit        and start the timer. The timer will stop when the fluid has        penetrated into the Reference Absorbent Pad and fallen below the        level of the electrodes in the strikethrough plate.    -   Record the time indicated on the electronic timer.    -   Remove the test assembly and discard the used Reference        Absorbent Pad. Rinse the electrodes with the 0.9% NaCl aqueous        solution to “prime” them for the next test. Dry the depression        above the electrodes and the back of the strikethrough plate, as        well as wipe off the dispenser exit orifice and the bottom plate        or table surface upon which the filter paper is laid.    -   Repeat this test procedure for a minimum of 3 replicates to        ensure the strikethrough target of the Reference Absorbent Pad        is met. If the target is not met, the Reference Absorbent Pad        may be out of spec and should not be used.    -   After the Reference Absorbent Pad performance has been verified,        nonwoven substrate samples may be tested.    -   Cut the required number of nonwoven substrate specimens. For        nonwoven substrates sampled off a roll, cut the samples into 10        cm by 10 cm sized square specimens. For nonwoven substrates        sampled off of a consumer product, cut the samples into 15 by 15        mm square specimens. The fluid flows onto the nonwoven substrate        specimen from the strike through plate. Touch the nonwoven        substrate specimen only at the edge.    -   Neatly stack 5 plies of the Reference Absorbent Pad onto the        base plate of the strikethrough tester.    -   Place the nonwoven substrate specimen on top of the 5 plies of        filter paper. Two plies of the nonwoven substrate specimen are        used in this test method. If the nonwoven substrate sample is        sided (i.e., has a different layer configuration based on which        side is facing in a particular direction), the side facing the        wearer (for an absorbent product) faces upwards in the test.    -   Place the strikethrough plate over the nonwoven substrate        specimen and ensure that the center of the strikethrough plate        is over the center of the nonwoven substrate specimen. Center        this assembly under the dispensing funnel.    -   Ensure that the upper assembly of the strikethrough tester is        lowered to the pre-set stop point.    -   Ensure that the electrodes are connected to the timer. Turn the        strikethrough tester “on” and zero the timer.    -   Run as described above.    -   Repeat this procedure for the required number of nonwoven        substrate specimens. A minimum of 5 specimens of each different        nonwoven substrate sample is required. The average value is the        32 mN/m low surface tension strikethrough time in seconds.

Specific Surface Area

The specific surface area of the nonwoven substrates of the presentdisclosure is determined by Krypton gas adsorption using a MicromeriticASAP 2420 or equivalent instrument, using the continuous saturationvapor pressure (Po) method (according to ASTM D-6556-10), and followingthe principles and calculations of Brunauer, Emmett, and Teller, with aKr-BET gas adsorption technique including automatic degas and thermalcorrection. Note that the specimens should not be degassed at 300degrees Celsius as the method recommends, but instead should be degassedat room temperature. The specific surface area should be reported inm²/g.

Obtaining Samples of Nonwoven Substrates

Each surface area measurement is taken from a specimen totaling 1 g ofthe nonwoven substrate of the present disclosure. In order to achieve 1g of material, multiple specimens may be taken from one or moreabsorbent articles, one or more packages, or one or more wipes,depending on whether absorbent articles, packages, or wipes are beingtested. Wet wipe specimens will be dried at 40 degrees C. for two hoursor until liquid does not leak out of the specimen under light pressure.The specimens are cut from the absorbent articles, packages, or wipes(depending on whether absorbent articles, packages, or wipes are beingtested) in areas free of, or substantially free of, adhesives usingscissors. An ultraviolet fluorescence analysis cabinet is then used onthe specimens to detect the presence of adhesives, as the adhesives willfluoresce under this light. Other methods of detecting the presence ofadhesives may also be used. Areas of the specimens showing the presenceof adhesives are cut away from the specimens, such that the specimensare free of the adhesives. The specimens may now be tested using thespecific surface area method above.

Obtaining Samples of Nonwoven Barrier Cuffs

Each surface area measurement is made up of nonwoven barrier cuff (e.g.,50, 51) specimens taken from absorbent articles to reach a total samplemass of 1 g. The specimens are cut from the barrier cuffs in areas notdirectly bonded to the absorbent article (e.g., area 11 of FIG. 3) usingscissors. An ultraviolet fluorescence analysis cabinet is then used onthe specimens to detect for the presence of adhesive, as the adhesivewill fluoresce under this light. Other methods of detecting the presenceof adhesives may also be used. Areas of the specimens showing thepresence of adhesive are cut away from the specimens, such that thespecimens are free of the adhesives. The specimens may now be testedusing the specific surface area method above.

Fibril Length Measurement Test

1) Using a software program such as Image J software, measure the numberof pixels within the length of the legend on an SEM image of a nonwovensubstrate using a straight line (i.e., a line with a length and nothickness). Record the length of the line and the number of microns thatthe legend corresponds to.

2) Pick a fibril and measure its length from its free end to the endoriginating out of the fiber as best visualized. Record the length ofthe line.

3) Divide this length by the length of the legend in pixels and thenmultiply by the length of the legend in microns to get the length of thefibril in microns.

If the fibrils are long and curly, then the length of such fibrils istaken in linear increments.

Mass-Average Diameter

The mass-average diameter of fibers is calculated as follows:

${{mass}\mspace{14mu} {average}\mspace{14mu} {diameter}},{d_{mass} = {\frac{\sum\limits_{i = 1}^{n}\left( {m_{i} \cdot d_{i}} \right)}{\sum\limits_{i = 1}^{n}m_{i}} = {\frac{\sum\limits_{i = 1}^{n}\left( {\rho \cdot V_{i} \cdot d_{i}} \right)}{\sum\limits_{i = 1}^{n}\left( {\rho \cdot V_{i}} \right)} = {\frac{\sum\limits_{i = 1}^{n}\left( {\rho \cdot \frac{\pi \; {d_{i}^{2} \cdot {\partial x}}}{4} \cdot d_{i}} \right)}{\sum\limits_{i = 1}^{n}\left( {\rho \cdot \frac{\pi \; {d_{i}^{2} \cdot {\partial x}}}{4}} \right)} = \frac{\sum\limits_{i = 1}^{n}d_{i}^{3}}{\sum\limits_{i = 1}^{n}d_{i}^{2}}}}}}$

where

fibers in the sample are assumed to be circular/cylindrical,

d_(i)=measured diameter of the i^(th) fiber in the sample,

∂x=infinitesimal longitudinal section of fiber where its diameter ismeasured, same for all the fibers in the sample,

m_(i)=mass of the i^(th) fiber in the sample,

n=number of fibers whose diameter is measured in the sample

ρ=density of fibers in the sample, same for all the fibers in the sample

V_(i)=volume of the i^(th) fiber in the sample.

The mass-average fiber diameter should be reported in μm.

Gravimetric Weight Loss Test

The Gravimetric Weight Loss Test is used to determine the amount oflipid ester (e.g., GTS) in a nonwoven substrate of the presentdisclosure. One or more samples of the nonwoven substrate are placed,with the narrowest sample dimension no greater than 1 mm, into acetoneat a ratio of Ig nonwoven substrate sample per 100 g of acetone using arefluxing flask system. First, the sample is weighed before being placedinto the reflux flask, and then the mixture of the sample and theacetone is heated to 60° C. for 20 hours. The sample is then removed andair dried for 60 minutes and a final weight of the sample is determined.The equation for calculating the weight percent lipid ester in thesample is:

weight % lipid ester=([initial mass of the sample−final mass of thesample]/[initial mass of the sample])×100%.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

All documents cited herein, including any cross referenced or relatedpatents or patent applications, are hereby incorporated by reference intheir entirety unless expressly excluded or otherwise limited. Thecitation of any document is not an admission that it is prior art withrespect to any invention disclosed or claimed herein or that it alone,or in any combination with any other reference or references, teaches,suggests, or discloses any such invention. Further, to the extent thatany meaning or definition of a term in this document conflicts with anymeaning or definition of the same term in a document incorporated byreference, the meaning or definition assigned to that term in thisdocument shall govern.

While particular embodiments of the present invention have beenillustrated and described, those of skill in the art will recognize thatvarious other changes and modifications can be made without departingfrom the spirit and scope of the invention. It is therefore intended tocover in the appended claims all such changes and modifications that arewithin the scope of this invention.

1. A nonwoven substrate comprising a layer of fibers, wherein aplurality of the fibers each comprise a plurality of fibrils extendingoutwardly from a surface of the fibers, and wherein the plurality offibrils comprise a lipid ester.
 2. The nonwoven substrate of claim 1,wherein the plurality of fibers are formed from a composition comprisinga polyolefin and the lipid ester, and wherein the composition comprisesat least 11% of the lipid ester, by weight of the composition, whereinthe lipid ester has preferably a melting point in the range of 40° C. to150° C.
 3. The nonwoven substrate of claim 1, wherein the average lengthof the fibrils from the surfaces of the fibers to free ends of thefibrils is in the range of about 0.5 μm to about 20 μm.
 4. The nonwovensubstrate of claim 1, wherein the average hydraulic diameter of thefibrils is in the range of about 100 nm to about 800 nm.
 5. The nonwovensubstrate of claim 1, wherein the layer of fibers comprises spunbondfibers, meltblown fibers, or fine fibers.
 6. The nonwoven substrate ofclaim 1, wherein at least some of the fibrils extend radially outwardlyfrom the surface of the fibers in a central longitudinal third of atleast some of the fibers.
 7. The nonwoven substrate of claim 1, whereinthe plurality of the fibrils grow out of the surface of the fibers atleast 24 hours post-nonwoven substrate formation under ambientconditions.
 8. The nonwoven substrate of claim 1, wherein the fiberscomprising the plurality of fibrils are free of droplets of the lipidester.
 9. A nonwoven substrate comprising a layer of fibers, wherein thelayer of fibers comprises a plurality of bonds, each bond comprising abond area, and wherein a plurality of fibrils extend outwardly from asurface of at least one of the bond areas.
 10. The nonwoven substrate ofclaim 1, wherein the plurality of fibrils consist essentially of a lipidester.
 11. The nonwoven substrate of claim 9, wherein the plurality offibrils comprise glycerol tristearate, and wherein the glyceroltristearate has a melting temperature above 35° C. and/or wherein aplurality of the fibers comprise fibrils extending radially outwardlyfrom a surface of the fibers and/or wherein the nonwoven substratecomprises a second layer of fibers, and wherein the fibers of the secondlayer of fibers are substantially free of fibrils and/or wherein thenonwoven substrate comprises a second layer of fibers, and wherein aplurality of fibrils extend radially outwardly from a surface of atleast some of the fibers in the second layer of fibers and/or whereinthe nonwoven substrate comprises a second layer of fibers, wherein thelayer of fibers comprises spunbond fibers, and wherein the second layerof fibers comprises meltblown fibers or fine fibers and/or wherein thefibers are formed from a composition comprising at least 11% of a lipidester, by weight of the composition.
 12. A nonwoven substrate comprisinga layer of fibers, wherein a plurality of the fibers comprise fibrilsextending outwardly therefrom only after a time period, and wherein thetime period is greater than about 24 hours post-nonwoven substrateformation under ambient conditions.
 13. The nonwoven substrate of claim12, wherein the time period is greater than about 100 hourspost-nonwoven substrate formation under ambient conditions.
 14. Thenonwoven substrate of claim 12, wherein the fibrils are a first color,wherein the plurality of fibers are a second color, and wherein thefirst color and the second color are different.
 15. The nonwovensubstrate of claim 12, wherein the plurality of fibers are free ofdroplets of a lipid ester.
 16. The nonwoven substrate of claim 9,wherein the plurality of fibrils consist essentially of a lipid ester.